Archive of Our Own

In hindsight, Izuku should have realized just how bad of an idea being at this hero event was. 

His heat was quickly approaching and this… thing with Katsuki was relatively new. It would be the first heat they shared, his brain wasn’t fully coherent. But in his defense, he wanted to see the alpha in a suit. For all the times they were together or shared a bed, he had never seen something more attractive than how that sleek black tuxedo looked spread across those broad shoulders or how those pants fit snugly against his waist. 

Izuku clenched his ass to keep in the slick.

But it wasn’t seeing Katsuki that was the issue…it was seeing him with others that made something burn in the back of his throat and his fangs itching underneath his gums. For all that the alpha hated people, he was too good at schmoozing at events. His tall frame and cocky grin got him a lot of unwanted attention. Not that he paid it any mind, he said so quite a bit in bed that he only ever had eyes for Izuku but–

Izuku is the one who doesn’t want the attention on him. He cared. He cared a lot about it. 

He was seated at one of the corner tables, fingers tapping against the soft white fabric as he watched Katsuki talk to a pretty brunette. Objectively she was gorgeous, all glowing skin and petite. Her body moves fluidly and she laughs, fingers delicate against glossed lips. The olive green dress was decorated with pretty diamonds- everything about her screamed perfection. His head raised a bit, nose flared as he took in the scent of perfume and the sweet scent of an aroused omega. 

He hated her, then and there. Immediately.

Not her fault. 

Katsuki was obviously courting him and sure,  that didn’t mean he was up for grabs. 

“It’s just banter…” He mumbled to himself. Katsuki turned his head to look at him then, their eyes met in silent conversation until the blood rushed to Izuku’s face. What felt like minutes had only been a second, both of them snapped back to reality when little Miss Perfect put a hand on his shoulder and dragged her palm down the sleeve of his tux. 

Katsuki put on a gentle smile, a let-her-down-easy thing. But Izuku was already up and at his side, his scarred hand a sharp contrast against her unmarred skin. His grip was tight, the woman's face scrunching up in discomfort. 

“He’s not available.” Izuku’s words fell out on a light growl, lips upturned just so to show a hint of teeth. “Sorry for the inconvenience.” 

“Oh! I didn’t–” She pulled her hand back, rubbing at her wrist. “I was not aware he was in a relationship. He didn’t smell taken and he didn’t have a mark I- I would hope you understand my intentions were not malicious.”

And she meant it, the roaring in Izuku’s ears settled as logic hit him. “I’m so sorry for that…it’s…we’re new. Honeymoon phase or whatever they call it, please forgive me.” 

Jenna, Izuku had eventually learned her name, simply laughed it off, recalling what it was like when she first got involved with her ex-lover. They shared stories and networked. Katsuki and Izuku ended up wandering around the building, the other not bringing up his earlier behavior but some glances let him know they’d talk about it later. 

He could just blame it on the heat, but, Izuku could not get the image of someone touching Katsuki and the alpha leaving him for someone else out of his head. This was something different altogether, a feeling he hadn’t had the misfortune of navigating until now.

His mood soured in the middle of talking with people he just couldn’t care about and he excused himself. His mind was aflutter with what ifs…what if Katsukyi found Jenna more attractive? What if he wasn’t as into Izuku as he said because he wasn’t dainty or took shit just because of his dynamic. Thoughts unbeknownst to him, Katsuki followed him down to the lobby, the thick scent of his alpha like a magnet. Izuku turned to face that piercing red gaze. 

“Where are you going?” Katsuki sounded more concerned than anything, but having that attention on him had his slick sliding down his thigh. He watched in horror as Katsuki’s nose flared and his eyes briefly shot down to Izuku’s crotch. 

“Back to our hotel room. I’m not feeling well.” 

“I’ll come back with y-”

“No!”  

His shout had heads turning in curiosity, all Izuku could see was the look of hurt on Katsuki’s face. “Hey nono, you didn’t- I promise you didn’t do anything Kacchan.” Izuku moved forward, leaning his forehead against Katsuki’s chest, purring at how a large hand sat heavily against his hip. “I just…need a bit to myself, my head is all weird and I’m not acting right. Maybe my upcoming heat is making me act weird.”

Katsuki was silent for a moment before sliding his hands to cup Izuku’s face, forcing him to look up at him. “You sure you’re ok?"

Izuku nuzzled into his palms, kissing the indent beneath his thumb. “I am, I promise. I can take care of myself.”

Katsuki smiled then, a private one just for the two of them. “I know baby…but I like taking care of you, y’know? I’ll see you at the hotel.” 

Izuku had never felt more at peace in his life than when Katsuki’s lips were so gentle against his. Gentle and doting. 

                                                                                        _________

Izuku was not at peace!

Between the drive back to the hotel and the walk back to his room, Izuku found himself treading between wallowing and anger; replaying what Jenna had said over and over in his mind until his jaw twitched and hands balled into fists. 

“He didn’t smell taken and, he didn’t have a mark.”

She was right.

She was right and he ate him alive because after taking the time to google his symptoms he found out he was jealous and it made so much sense. He was jealous, his instincts rampant right before his heat. Just the idea of Katsuki anywhere near someone that wasn’t him left him boiling.

Sweat was building at his hairline, vision blurring as he sifted through his emotions. He felt empty and needy— Katsuki needed to do this but he wanted him back more to take care of him. His shirt came off first, fabricating a light pleasure against his nipples.

As he unbuttoned his pants, the urge to have Katsuki with him became unbearable in a sudden rush. He found himself in the bathroom rummaging through the pile of Katsuki’s dirty clothes until he found his briefs. Izuku purred, bringing the fabric to his nose and inhaling; the heady musk a welcoming scent. His own underwear was soaked, the image of Katsuki undressing and the scent clouding Izuku’s brain had pushed his heat to a head. 

The bed was comfortable, Izuku blacked out somewhere between the bathroom and the cool sheets, three fingers dee[ in his ass. Every rub at the bundle of nerves inside of him had him on a heavy inhale where his nose was shoved against the gusset of Katsuki’s briefs. His alpha’s scent was strong, potent - reassurance that Katsuki was something that no one else could be for him.

Katsuki was his.

His alpha. 

His object of desire. 

A fourth finger stretched him easily, his body hollow-feeling and needy. He wanted to submit, to give himself entirely to his kacchan. But the alpha needed to understand who he belonged to…no, the world needed to learn.

He thrusted his fingers in and out, a rhythm to match every inhale of Katsuki’s intoxicating scent. His rim gave way easily, the slick making noises Izuku imagined were from Katsuki’s knot fucking in and out. Soon, he thought. The mental image of Katsuki knotting him finally, his teeth against his neck with his scent overwhelming him brought on a violent orgasm, body pushing forward until the top of his head pressed against the cool headboard. 

Izuku watched the clock tick in a blurred daze, his fingers lazily circling his rim as he waned from the high. His body was warm, sweat dripping on his pillowcase- he debated between going again but he was so tired and his alpha would be here soon…no need to ruin it for the both of them. 

Sleep took him quickly then, nose buried in Katsuki’s briefs. 

When the sound of the door clicking open and closed woke him up, he was burning. Katsuki’s scent wafting towards him. His eyes could barely open when he felt large hands on either side of his face, cradling him so gently and if it weren’t for the raw need he had for him, Izuku would have burst into tears. 

“ Alpha… ” Izuku moaned, nuzzling into his palms. He felt a flash of heat against his cheek, and let his eyes look into the sharp red gaze. Katsuki’s pupils had blown, his musky scent sharpened, heavy, and full of want and need. All of it was for him, for his omega. The hint of fang peaking from behind his lips–

Rut. 

Izuku had triggered the start of his rut. If that wasn’t a sign they were meant for each other, he thought with a shiver, he wasn’t sure what was. 

Katsuki pushed him back gently against the mattress, undoing his tie and shrugging off his blazer, letting it fall to the floor agonizingly slow. Izuku inhaled and spread his legs to show how wet he was as he took in the sharp definition of muscle, the broad span of his alpha’s shoulders, and a chest Izuku fantasized about biting into. He wanted to climb inside of him until Katsuki didn’t know anything but him. 

“Jesus baby- I’ll give it to you just be patient.” Katsuki takes his face in his hands and smashes their mouths together. Izuku’s arms go around his neck as the alpha fits himself between his legs, the soft fabric of his dress pants tingling the inside of his thighs. Katsuki lets out a growl, hands sliding down Izuku’s body until they find his ass and grip hard, encouraging Izuku to wrap his legs around his waist. 

The alpha was pressed against him, rubbing their erections slowly as they kissed. Izuku shifted his face and opened his mouth to gasp, Katsuki wasted no time and slid his tongue inside, taking his time to explore the taste of Izuku. They’ve kissed before, heated, but it’s never been like this. Izuku’s never experienced a heat with a partner, much less someone so compatible and this moment has been a collective of ‘almosts’ building up between them. 

His heat hit a brief lull, his senses sparked to life and Izuku let himself savor the taste of Katsuki. The alpha’s saliva was almost overwhelming, he remembered somewhere that an alpha would overproduce saliva during sex to alleviate the pain of fang growth and he shuddered at the thought. He broke away, gasping, staring with fascination at Katsuki’s canines seeming to have grown in size. His thumb ghosted over the length of one, eliciting a groan from the alpha before Katsuki took his thumb into his mouth and sucked. 

Izuku watched, mesmerized. 

“Kacchan I– I want to suck you off.” 

Katsuki pulled back from his thumb, a wet pop following. He swallowed thickly, Izuku watching the rise and fall of his Adam’s apple as he did. “Fuck…whatever you want, baby.”

Whatever he wanted, huh? 

“Want you t’knot my mouth. Wanna take care of you, alpha .” Izuku was lifting both of them, his quirk giving that extra push and Katsuki was on his back with a filthy grin. He stared at those fangs, crawling up against Katsuki’s larger frame to press a gentle kiss at the juncture of his shoulder and neck. The alpha trembled a bit, chest rumbling with a deep purr that had him cooing in response. 

“I missed you,” Izuku mumbled, nipping at the spot he kissed. 

“I missed looking at you.” Another bite at his shoulder, nosing down to the crevice between his arm and his chest. “Missed smelling you.”

“Baby I was only- oh fuck !” Katsuki lurched, head thrown back as Izuku lifted his arm to nuzzle at the hair under his arms. He mumbled how good Katsuki smelled, ass clenching at the scent before he licked a long strip along the underside. Articulating how tasting him made Izuku feel just wasn’t in the books, the salty sweat along the bumps of his tongue and the musk beneath the fading deodorant had another rush of slickness flowing down his backside. 

Katsuki’s nostrils flared, a deep intake of air and a hitch in his breath following not soon after. 

“You taste so good...can’t wait to feel you in my throat, alpha.” Izuku left bites down Katsuki’s chest, lips pinching at a nipple as his hands appreciated the definition of muscle that was his alpha’s chest. His tongue followed the divots of Katsuki’s abs, reveling in the way the muscles pulled taught as he worshipped the definition there. 

The closer he got to Katsuki’s crotch, the more his heat pushed him past a boundary of lucidity. 

It was warm at that event, Katsuki’s quirk making him sweat a little more but it was nothing short of a gift in Izuku’s eyes. He rested his cheek against the darker blonde hair of the alpha’s happy trail, looking up at him and watching how he caved under his touch; his face pinched, vulnerable as he stared right back at him.

“You’re lookin’ real pretty down there.” Katsuki teased.

Izuku laughed, fingers playing with the button of his dress pants, taking his time in watching the bright gold zipper be pulled down against the strain where Katsuki’s cock was trying to push through. “Take your pants off.”

“Mmm…demanding, huh omega?”

“Kacchan please !”

Katsuki seemed pleased with the begging, raising his hips to throw his pants fuck all onto the floor. Izuku gave him an appreciative once over, stomach curling with heat at how his briefs his nothing. Before Katsuki could say anything smart, Izuku mouthed at the length of his cock through the fabric, tonguing at the wet patch of pre at the head of his cock. Whatever Katsuki was going to say was cut off by a moan. 

He found a spot just under the head, the tip of his tongue teasing and Katsuki helplessly bucked his hips into the touch, watching as Izuku’s soft lips parted around what his underwear allowed. Izuku didn’t pull them down, just kept his mouth on whatever had Katsuki whining- lived in the thrill of making someone so powerful as Katsuki cave with just a touch. 

Pulling the fabric down Katsuki was like watching cooking porn, Izuku had no way else to describe it. The sharp contrast of black sliding down toned thighs and the alpha’s heavy cock slapping against his stomach when it was relieved of its restraint, he couldn’t stop the tear that fell down his face. 

He was burning up, his face finding its way to the crevice where Katsuki’s thighs met his balls, taking deep inhales of that scent. Nosing his way down, Katsuki lifted his hips up to give him access to his perineum, the omega had wasted no time in getting his tongue on it then. His tongue was lax as he licked slowly against the line of flesh until his nose was under his balls and his ass twitched at how the muscles spasmed and Katsuki whispered an ‘oh fuck’. It was amazing, Izuku thought to himself, how great his alpha was to let him somewhere so intimate. 

But Izuku wanted every part of Katsuki to smell like him, and as he bit gently at the sensitive flesh and sucked a deep mark, he realized he meant every part. 

The gasp was ripped from Katsuki’s throat when Izuku's tongue found the rim of his ass, licking the sweat there, worshipping the taste of him. His hands were scratching gently at the sides of his waist, ghosting over the v of his adonis belt before grabbing at his cock, squeezing and tugging at a slow pace as he ate him out.

“Oh fuck- Izuku!” Katsuki said between gritted teeth, hand flying to push desperately at whatever he could of Izuku’s head, the omega was relentless in wanting to taste, the heat clouding him until “If you keep that up I’m gonna cum, asshole!”

Izuku’s head shot up at that, whimpered because he wanted Katsuki to cum in his throat…he needed—

“C’mere baby it’s ok,” Katsuki said as he brought Izuku’s face to his, tongue lapping at the shine of spit on his lips. Their kiss was slow, more intimate. A reassurance for Izuku that he did nothing wrong, that his alpha still wanted this with him.

“Good?” Katsuki asked, thumbing a sensitive spot behind his ear, scenting and rubbing softly in little circles. Izuku felt loved. 

Wanted. 

Izuku nodded, pressing a kiss to Katsuki’s lips before diving back to mouth at his balls. His mind was fully immersed in his hormones now, instinct driving him to please and to own. 

Katsuki scooted back and leaned back until his shoulder settled against the headboard, legs opening. Izuku lifted them up by his thighs, pushing himself forward until they rested on his shoulders and his face was pressed against his cock. 

He felt small like this, one of the alpha’s thighs seeming to dwarf him. It felt good, right even, Katsuki’s calves against the small of his back.

Izuku started it slow. He just looked at Katsuki for a moment, mouth slightly open, and then he ran his fingers up and down his length, down over his balls with a light squeeze, and back up. He took his time, let his heat sink in, surrounded by Katsuki’s scent, touched every inch of him he possibly could, and paid a little extra attention to the base of Katsuki’s cock.

He closed his fist around the middle of the shaft and his wet, pink tongue darted out to leak a bead of pre from the slit. Both of them moaned in unison, Izuku’s body growing hotter and hotter while goosebumps raised against his skin as he took the head into his mouth, sucking gently. Katsuki didn’t even try to keep himself quiet.

Izuku’s mouth was soft, hot in all the right places and he was too fucking good with it. He pushed himself down, agonizingly slow, in a way that left Katsuki breathless, until his nose was buried in the coarse hair above his cock, tongue playing with the slight swell of his knot. When he pulled back, he gently scraped his teeth along the length and the alpha hissed in please. Katsuki read that heats were intense and while the pheromones were sending him into a rut, control slipping with each bob of Izuku’s head, the omega was taking it slow. 

He was thorough, languid, and lazy in the way he used his mouth which made Kastuki melt into the bed, falling apart bit by bit at the attention. Katsuki put his hand on Izukus’ head, green hair sticking together with sweat but still impossibly soft, and made sure he let Izuku know how good he was doing, how much he was appreciated for doing this; panting praises and whispering all the things he’s going to do to him when he finishes knotting his pretty mouth.

Katsuki was painfully hard, rut hitting him on the side of his head like a train and Izuku had fully succumbed to his heat, no longer responding with words but with coos and purrs. He didn’t want to black out for this, didn’t want to lose this moment to the rush of hormones and make their first time something forgettable. 

He said as much, earning him a stare.

Then, Izuku slid his hands down and gripped him around the base, squeezing against the pronounced swell, he bobbed down, lips touching his fingers and he moaned. The vibrations sent a zing of electricity up his spine. Katsuki sucked in another breath, eyes rolling into the back of his head as he moaned. 

“Omega -” 

Izuku did it again, eyes solely on Katsuki with an intensity that had something inside of him caving. He wanted this.

He fucking needed Katsuki to knot him and his patience, restraint, sanity, or whatever the fuck he could call it had dissolved. He would give his little omega everything he wanted.

Katsuki had knotted his hand before, refusing to do it with someone that wasn’t right for him but– in his four walls after he started courting Izuku, he knew this would be the inevitable. The high emotions mixed with the rut made this something he couldn’t avoid, powerless to do anything but let it happen. 

Driven by impulse, he made a desperate noise, a choked sound as his hips came off the bed, fucking himself into Izuku’s mouth before he could stop. Izuku’s focus had shifted, no longer worshipping but intent, hand tugging at Katsuki’s balls, a finger slipping behind to rub at his taint. Katsuki growled and whined quickly after in a plea. Izuku’s grip on the base of his cock tightened, eased and tightened again. 

Katsuki’s toes curled, sliding down the headboard with his head thrown back and his head pulling sharply at Izuku’s hair, trying to push him past his fist.

Izuku bobbed in long pulls, cheeks hollowed as he moaned around his cock, gradually working his way lower and lower each time he came down. His grip on his base fell into the same rhythm, an array of sensations that was unbearably good, leaving Katsuki feeling crazed, out of control. He fumbled one of his hands to Izuku’s neck, index and middle touching the base of his throat and he could feel his cock there. He panted, his hold on Izuku tightening like he was afraid he’d stop.

Watching Izuku’s lips around his cock, his throat expand as it made room for him and he hadn’t even knotted yet…it was doing something to him. Izuku was made for this,made for him. He wasn’t even sure how Izuku was going to fit his knot in his mouth, he wasn’t small by any means, but he was going to make it happen. He wanted his knot so far in his throat for as long as he could take it until he could smell himself on Izuku’s face, and taste himself on his tongue. Everything about Izuku needed to be about him.

Izuku wanted it too, making hungry noises as he sucked, flexing his neck and shoulders as he worked his mouth down, like he was greedy for it, like he wanted Katsuki’s knot so bad, just as much as he wanted to give it to him. Katsuki could feel the sudden expand of flesh then, pressing against the palm of Izuku’s hand and he watched as his fingers no longer fit fully around it. The omega made a pleased noise, squeezing down in a way that had Katsuki moaning. “I’m close,” He choked out.

When Izuku took his hand away, Katsuki could see how swollen the base of his cock was, hot and aching, the skin a deep shade of red, pulled taut. Izuku backed off, until the head was in his mouth, tongue swirling deliciously around it as he opened his eyes and looked up at him, and then slowly sank back down, down and down and down until his mouth met the thickest part of Katsuki’s still growing knot. 

Katsuki watched, fascinated as Izuku kept going down, eyebrows furrowing in concentration as he bore down, and then the knot slipped in to rest on his tongue, filling his mouth impossibly wide. 

They stayed like that for a second, Izuku breathing through his nose, Katsuki trembling, hands still on his hair and throat and then Izuku swallowed with the nastiest moan he’s ever heard, the soft flesh working around Katsuki’s cock and that was it. Katsuki came with a snarl, tears in his eyes, teeth grinding down, and hands clutching at Izuku’s shoulders desperately as he shot down Izuku’s throat.

Katsuki has fucked around, but this? It’d never been intense like this. This was all for his little omega that was working his cock like it was his. Katsuki felt like he was coming with his entire body, every muscle pulled tight and he groaned through clenched teeth as he filled Izuku’s mouth, pulsing in the wet, warm space, crowding his tongue and pressing against the back of his teeth.

Izuku was swallowing in wet, thick gulps as his knot swelled in earnest, fully locking behind Izuku’s teeth. 

“Fuckin’ shit, Zu,” Katsuki praised “You’re so fucking good to me, baby. Gonna stuff you with my come– gonna give you so much of it. Can you take it?”

Izuku made a sound, fingers digging into Katsuki’s hips and thighs, he couldn’t talk with his mouth full and the alpha was a little smug about that. All he could do was ride out the high of his orgasm as he let his omega take what he wanted, shivery tension building at the base of his spine with every spasm. The pulses kept coming, one after the other, Katsuki shooting deep down Izuku’s throat, each one getting longer and slower, pushing air from him. A tear ran out from Izuku’s eye, onto Katsuki’s stomach but he never let up. 

Just kept moaning and swallowing, moaning and swallowing. 

“Such a good boy,” Katsuki murmured, thighs twitching at a wet swallow as he wiped the wetness from Izuku’s eyes. “Doing such a good job, baby.”

He’d experienced ruts before, but alone, never with a partner– with Izuku it was just more.  

Time escaped him, he didn’t know how long they were in this position, how long Izuku had spent making hungry noises as he swallowed every drop Katsuki gave him. Katsuki tightened his stomach, clenched his toes, and gritted his teeth with a cry as the last, overwhelming pulse of come made its way down Izuku’s throat, hands loosening on their grip and just petting, praising while he rode out the feeling. His hips rocked, gentle not to hurt his omega, taking in the feel of Izuku’s throat around his cock, his tongue pressing heavy and flat against his knot. He couldn’t push himself any deeper, despite his desperation to do so. 

“Can’t wait to be inside you, Izuku. Can’t wait to make you mine…this- you’re going to feel so good on my cock I promise.” And he meant it, he couldn’t imagine what he would feel like to knot inside Izuku for the first time, said as much on a high whine as another wave of pleasure hit him. 

Through the daze, he realized Izuku had come on the sheets, one hand reaching behind to finger himself as Katsuki kept rocking up into that tight, warm heat, falling back against the bed. Boneless as he was, his grip was still tight on Izuku’s shoulders and he eased it gently, looking down at the red mark of his fingers there. 

What a thrill that was. 

When his cock softened, 20 minutes later, Katsuki noticed, Izuku popped off with a cough, resting his forehead against Katsuki’s stomach. 

“You alright?” Katsuki asked softly, comforting. Izuku nodded, eyes unfocused reaching blindly for Katsuki’s hand until their fingers intertwined. Katsuki pulled him up, chest to chest, holding his face up with one hand to press a kiss against Izuku’s swollen lips. 

“You’re insane, nerd,” 

“-ne,” Izuku mumbled. 

“Hm?”

“Mine. Kacchan’s mine .” God his voice was hoarse, so fucked out and the streak of possessiveness was doing it for him.

“I am, baby. All yours.” But Izuku was already asleep, Katsuki falling not far behind with the feel of Izuku’s heartbeat against his,

Katsuki wakes some time later on his back, Izuku grinding against his thigh while he fingered himself. The scent of heat was suffocatingly thick in the air, Izuku rubbed his cheek against his chest, kissing whatever amount of skin he could while moaning Katsuki’s name. Wordlessly, he lets his hand wander down the line of Izuku’s spine, index pressing down at the base just to watch the pretty thing on him squirm. He could feel how wet he was, hand gripping hard at the swell of Izuku’s ass before he slid his fingers in next to Izuku’s.

“Kacchan– nff, please!” 

“C’mere Izuku…let me kiss you.” Izuku does, in a jerked reaction, Katsuki wasting no time in gripping his chin with his other hand and squeezing until Izuku gasped. He’s quick to force his tongue inside, fucking it into Izuku’s mouth, swallowing down the moans as he adds a second finger with Izuku’s three. “So stretched out for me baby…how long were you doin’ this?”

“Feels good- it’s not enough, Kacchan…I want more.” 

“What do you want?”

“You.”

Katsuki turned them over with a growl.

Izuku’s leg spread on instinct, crooning at how easily the alpha fit between them. He slid his already hard cock against Izuku’s— preening at the difference in size. He lined them up, twisted, and swallowed at how much he would fill Izuku— the head of his cock resting just underneath his navel and all he wanted to do at that moment was to dig in deep and mark Izuku where no one else could. 

“Turn around for me.” 

Izuku rolled and pushed upwards, grinding his ass into the large hand on his ass as he arched up off the soft sheets, waiting and wanting. Katsuki stares, his hand slipping from kneading Izuku’s ass to brushing his fingers against his drenched hole

“Baby you’re so fucking wet for me,” Katsuki moans. 

Katsuki leans over him, plastering against his back and Izuku can feel Katsuki’s nose just behind his ear. “N’ you smell so good, fuck. Need to—want to be inside you. Is that—Can I?”

“God, yes,” Izuku arched his back even further in response and moaned when Katsuki pushed his thick fingers past his rim. “Kacchan, please .”

He can feel Katsuki's mouth at the back of his neck, and those light touches paired with his fingers spreading his hole was so much, yet not enough.

He curls his arms under a pillow and rests his cheek on top of it, spreading his knees so his ass is further on display for Katsuki and sighs happily when the alpha pulled his digits back and sank them to the hilt inside of him.

Katsuki put force into his arm, crooking his index finger inside of Izuku just right until it hit his prostate and suddenly everything became too much yet not enough. Izuku pushed himself back on the alpha’s fingers and angled his head to see how handsome Katsuki looked with that confident smirk on his face. 

Katsuki’s mouth dragged across Izuku’s neck and cheek, inhaling his scent as he went along before slotting his lips against the omega’s, licking and biting and sucking at his lower lip until it was cherry red. Izuku is distracted enough by the taste of Katsuki’s tongue, so entranced in everything his alpha tasted and smelled like that the rush of an orgasm from Katsuki fucking his fingers in and out of his body hit him like a train. 

Izuku tensed, once, twice, Katsuki still fingering him through his orgasm and licking his way into Izuku’s mouth while he cried out. They kissed languidly, the movement inside of him turned gentle as his alpha worshipped his mouth. His body spurs into warmth when Katsuki rubs at the swollen gland of his prostate and in the heat-muddled brain, Izuku couldn’t name a time when he felt any better in bed. 

When Katsuki pulled himself away from Izuku’s back and his fingers from his well-stretched rim, the omega whined, pleading for contact until he felt the swollen head of Katsuki’s cock push inside so slow.

Katsuki ignored the noises, blinded by the sight of his cock finally making its way into Izuku. His hand gripped Izuku’s ass, the other a tight vice on his waist, his thumb spread a cheek just to watch how wide his omega’s hole gave just to take him in. 

Halfway through, Katsuki started to fuck into him, moving the hand from the omega’s waist to push him against the mattress between the shoulder blades. “Ass up baby, I’m gonna rail your fucking lungs out.”

Izuku reached a hand out behind him, groping blindly for Katsuki’s hips or ass or something he can hold on to to make the alpha go harder, faster.

Katsuki is quick with it, grabbing Izuku’s hands and pulling them back as he fucks his cock so deep at an angle that has Izuku seeing stars. 

“ More.”

“Harder.”

“Faster Alph-”

Katsuki is not one to not follow directions, especially not when he guides Izuku’s hands to the headboard and barely gives him enough time to brace before he’s fucking the very breath from Izuku’s lungs. 

Their bed creaks under the force of his thrusts, Izuku’s head hitting the wood panel as his arms give out. He’s fucked relentlessly; Katsuki’s on one knee while the other is braced over Izuku’s leg, his foot digging into the mattress by his face. 

The omega pressed a kiss to the top of Katsuki’s foot, tongue trailing against the salty skin until he nipped at Katsuki’s ankle. It earned him a feral snarl in response and the feeling of swollen flesh against his rim.

“Zu, I can’t- oh fuck baby,” Katsuki had thrown his head back mid-sentence, Izuku looking back at him to see his mouth open and close as he spoke, drool spilling from the corner of his mouth as his eyes clenched shut. He could just barely make out Katsuki’s whimpers.

“Please baby let me knot you. I need, fuck, I need to knot you.”

“C’mon alpha fucking please,” Izuku’s eyes rolled back, head pressing into the pillow as he bit the fabric. “Knot me..fill me up, please! Want your pups so bad, Kacchan!”

Katsuki snarled again, nails digging bloody marks into Izuku’s skin as he forced the thickest part of his knot in Izuku, the sound of a wet pop making Katsuki roar so loud, Izuku could feel it in his bones. 

This feeling?

Surreal- Izuku couldn’t feel any part of his body, his brain narrowed in on the feeling of fullness in his stomach, the warm heat spreading as Katsuki’s cock pulsed thick ropes of cum inside of him. 

Katsuki has enough sense to grab Izuku’s cock. Two jerks and he was squirting against the sheets. He leaves a trail of kisses, sucking deep red marks into his pale skin. There’s a gentle prick of fangs as he does so and Izuku is left with the deep desire to ask for them buried right into the space between his neck and shoulder where he could show it off for everyone to see. 

But it would happen eventually.

Katsuki lowers himself, a window of gentleness that has his heart skip a beat as the alpha readjusts them, his back pressed firmly against Katsuki’s wide chest while the alpha rubs gentle circles just beneath his navel. “Can feel my right here, Zu,” Katsuki pressed in a bit, Izuku squirmed at the feeling of Katsuki’s fingers poking on where he was stuffed full from the outside. “Took me so well baby, you feel incredible.”

Izuku can only nod, heart in his throat, pliant and at the mercy of Katsuki’s petting and words.

Somewhere along the way they both fall asleep, Izuku waking up to Katsuki’s cock throbbing between his thighs, slick and cum an uncomfortable sensation. The throws of heat come and go, crashing into him like a wave and suddenly he craves, and then Izuku is filled with the desire to nest up with Katsuki. 

It’s disorienting. 

But one wave had hit him hard, vision blurred and Katsuki was suddenly on top of him, kissing him back into the mattress until he settled. “Doing ok?” God, his voice; that deep husk an arousing scratch in his ear.

“Mmm– need you again, Kacchan.”

“I’m here, always. What do you want now?”

Izuku gripped his cock, palmed down the length of it until he reached where Katsuki’s knot would form, squeezing with a confidence that only his heat could give him. The alpha flinched at the pressure, huffing out a small laugh. 

And for some reason all Izuku could think about was the way that other omega had put her hand on his bicep. How he had to sit there and watch someone flirt with his alpha while he kept his mouth shut and Katsuki had let it happen knowing Izuku was right fucking there. The thrum of OFA was a sudden rush, Izuku moved in a messy blur until he was straddling Katsuki’s waist and the alpha was staring at the ceiling yelling ‘What the fuck ?’.

Izuku looked down at Katsuki, a stain of hunger in his eyes.  

Katsuki stared up at him, taking the pretty sight in; Izuku had started fingering himself, raising and lowering his ass against the length of his cock as he did so. The unspoken “Watch me.” was thick in the air and the alpha found he couldn’t look away, even when the rough indent of a knuckle from Izuku’s finger brushed over a vein. 

Katsuki leaned in to kiss him, savoring the taste of him on his tongue. Izuku tasted sweeter than normal, he noted as he gripped the curly locks between his fingers. The omega pulled away soon after, defiant with the motion, a hand pushing Katsuki by the chest until he was leaning back against the headboard. 

His hair was mussed from where Katsuki’s fingers gripped at it, his neck dotted with dark red marks. The sensation of being inside Izuku had him feeling drunk, greedily taking in the image of freckled skin and pupils so dilated he could hardly see the green.

He watched the way Izuku’s stomach clenched as he fingered himself open. Watched the way Izuku’s mouth parted when he moaned and fuck he couldn’t wait till Izuku was screaming on his cock again.

A drop of slick falling on his thigh snapped him out of his hypnosis and he lunged forward again, swallowing Izuku’s surprised noise down with a deep kiss. Katsuki chased the taste of Izuku and the saltiness of his cum from earlier, took and took until Izuku protested for air.

Izuku pulled away, panting. The grip he had on Katsuki’s cock pushed him to the brink as he lined the head of his cock against his rim. 

“Don’t move, just watch. I’m gonna take such good care of you, Kacchan.” Izuku had whispered while sinking himself slowly until he was seated against Katsuki’s lap. 

Oh. Oh.

Katsuki’s eyes rolled back, hands flying to grip nasty bruises on Izuku’s thighs. He felt the way those thick muscles twitched under his fingertips. 

Izuku was hot and slick and perfect. He swiveled his hips, grunting, and Katsuki almost blacked out. 

“So big, Kacchan…I can feel you here. Feel how deep you are.” Izuku was a fuckin’ slut, somewhere in his brain Katsuki knew the nerd had something locked away but this? He didn’t know where his thoughts were going, but Izuku guided his palm to just below his navel, pushed against the soft flesh, and for a second Katsuki could feel the length of himself inside Izuku. 

Holy shit. 

Izuku lifted himself on strong thighs until the head of Katsuki’s cock kissed his entrance “Hands against the pillows. Don’t move.” and then he let himself fall down to the hilt.

“ Bfwuh… ” Katsuki smartly replied. The sudden switch of dominance left his brain short-circuited. 

Izuku swivels his hips and lets himself enjoy the high of having his alpha so deep inside of him. He braced his hands on Katsuki’s shoulders and shifted, all the alpha wants to do is put his hands on the, fuck, handmarks on Izuku’s waist but he was too obsessed with the idea of Izuku taking exactly what he needs from him. 

Instinct drove him to please, if his omega wanted this,l he would have it.

Izuku is all hot and slick and perfectly tight around him, riding him for all he’s worth taking whatever he wants and Katsuki feels his knot already starting to swell.

It does something to him, the way Izuku has taken charge, considering the omega is more than satisfied to let Katsuki take the lead. This is their first proper heat together, and knowing Izuku gets bold and brazen like this, akin to fighting a villain, is just as arousing as anything. 

Katsuki is putting this on a kink list. 

Izuku straddles him in a way that has put his chest at eye level with Katsuki, despite being told not to, Katsuki is not a strong man when it comes to Izuku. He wrapped an arm around Izuku’s waist and put his mouth on one of Izuku’s nipples. 

The minute his lips closed around them, Izuku moaned, loud and long and it was such a beautiful sound that Katsuki didn’t notice the small crackle of energy before Izuku slammed him back against the headboard by his throat. Pain blossomed at his shoulder blade, his teeth bared in reflex at the obvious challenge and though he wanted to protest, Izuku was still riding him.

“I said don’t touch,” Izuku snarled, teeth clacking in front of Katsuki’s face. Arousal curled around the air as Katsuki swallowed, submitting– Izuku kept his hand against his throat, thumb pressing in the sides just right. 

What had happened next was something he couldn’t describe. Izuku set a punishing pace, not once removing his hand from Katsuki’s neck and anytime the alpha got close, Izuku squeezed his throat and slowed his pace. 

Agony in the best way. 

Neither of them spoke, just the sickening sound of Izuku's slickened ass making room for Katsuki’s cock. Izuku’s grip was teetering on the lines of too tight, black spots dotting his vision, fading at the waves of pleasure from his omega robbing him of everything he had.

“C’mon Kacchan– a little longer for me, alpha!”

“Zuku I can’t– fucking hell baby you feel so good. Please slow down.”

Izuku ignored him, pressing down and grinding until the knot almost caught before forcing it out of him with a gasp. “Who do you belong to?”

Up and down. “You baby, just you.”

“Say it again.” Up and down.

“ You! ”

“ Good boy, Kacchan.” Katsuki crooned, hand flying up to grab but Izuku slapped it away. “Not yet.”

He slammed down on him again, Katsuki’s knot now popping in and out with a sickening squelch. The alpha beneath him was tearing at the pillow, every rise and fall of Izuku’s body only left another bit of fabric torn.

It fucking hurt so good but he had to– he couldn’t let Katsuki knot him until he said it. 

“Who do I belong to?” Izuku ground against his pelvis, hips swiveling so slow and he clenched down on that thick knot inside of him. Katsuki’s eyes were red, and tear streaks on his cheeks made him look so ruined— made Izuku feel so powerful. “Answer me, Kacchan.”

“M-me…fuck, baby. Just- me.”

“Good boy.” Izuku lifted, just until the widest part stretched his rim. Katsuki threw his head back with a rasped moan, chanting ‘ fuck fuck fuck’ to himself. “ Take me, Kacchan. Fill me! ”

He set an unrelenting pace, fingers digging into Katsuki’s pecs, nails indenting their presence before he tweaked a nipple. The alpha whined, hips raising to meet him thrust for thrust. His stomach was taut with restraint, mind screaming at him to take, take, take. 

To claim. 

Katsuki gripped one of Izuku’s thighs, the other at his waist as he forced him down on his knot for the last down. The omega was frozen, hips stuttering as he came all over Katsuki’s chest while the alpha suffered through the most intense orgasm of his life, the smell of them combined on his skin only pushing him into further bliss.

Katsuki nosed at the junction of Izuku’s neck and shoulder, a heavy purr as he waited for the omega to bare his neck in permission. Izuku jutted his chin up, eyes fogged, on instinct alone and it was all Katsuki needed to sink his fangs in deep. 

Izuku’s blood was metallic in his mouth, sweet as he fully claimed him. His omega’s mouth was wide open in shock, a spurt of clear fluid spraying across his stomach, joining the mess he already made.

Something… something right snapped into place.

They fell asleep to Katsuki pulling him against his chest, tongue lathering over the mark. His hands wrapped around Izuku’s distended stomach.

Izuku’s heat and subsequently Katsuki’s rut ends three days later.

They don’t leave the hotel for well over a week and Izuku has to deal with the most judgmental stares from the staff as they exit– he came in markless, and he was leaving with the most impressive mark he’s seen in his entire life. Leave it to Katsuki to overdo everything.

“You couldn’t have made it a little smaller?” Izuku hisses his complaint on the car ride home.

“Baby, my handprints are all over your body, just be glad that your neck is all they saw.” Katsuki was smug, not even the least bit sorry about it. 

Two weeks go by and Katsuki is crowding Izuku into bed, legs wrapped around his waist, large hands careful over his stomach, and his lips pressing gentle kisses to the mark on his neck. Izuku laughs, on a high like no other. Talk about Katsuki overdoing everything. 

Their first heat together, two weeks, and Izuku using so many pregnancy tests his friends got concerned. But breaking the news that he was carrying Katsuki’s pups was the greatest thing to watch; the tears building in the corner of Katsuki’s eyes, the way he was lifted into the air and shown such a rare smile reserved only for him, for special moments like these. The way Katsuki was surrounding him, enveloping him with his scent and purring so hard against his back it felt like a massager– it was so worth it. 

Izuku couldn’t stop the flow of tears as he laughed, Katsuki had spun him around, their foreheads touching as he wiped the tears away with his thumb with such care. Like Izuku was something fragile. 

“You’re carrying my pups…can’t fuckin’ believe how amazing you are, nerd,” Katsuki whispered, kissing his nose, under his eyes, and his cheeks until Izuku was laughing wetly. “Our first heat together…we’re really the best of the best, huh?”
“Yeah, Kacchan…guess we are, huh?”

“We gotta tell our shitty friends.”

“We do.”

Katsuki encouraged him to lie down, facing him with a determined look on his face. Their hands were intertwined, legs entangled with each other, and feet touching. Izuku wanted to be looked at the way Katsuki was looking at him for the rest of their lives and god he was so happy that he would get it. They whispered for hours, laughing like giddy teenagers falling in love for the first time as they talked about their future– how they’d be kickass heroes during the day and badass parents at night. They argued over names and debated over who would be the favorite parent until Katsuki had Izuku on his back and his name spilling in a breathy moan from between his lips. 

“ Mine and yours .”

“Always, Kacchan.”