Work Text:
Katsuki picks at his fingernail as he looks at the date on his phone screen.
July 15th. Why the hell did he decide to make his move on Deku’s birthday? He was nervous enough already. Izuku presented as an alpha before his 18th birthday, just as Katsuki had presented as a beta. It pisses him off. Not because he expected to be an alpha and instead the nerd presented as one, but because if he was stuck being a beta, why couldn’t Izuku be stuck with him? Suddenly Izuku was struck with a growth spurt and instincts he could act on; Katsuki felt left behind.
Katsuki had recognized his feelings after the war. He realized people don’t just throw themselves in harm's way for just anyone. With school ending, he felt the need to finally tell Izuku how he felt. He also knew that sooner or later that knothead was going to find an omega and forget all about him.
Katsuki could not let that happen.
He didn’t get the extra lessons about secondary genders because it was just an elective for betas and not a requirement. At the time, he preferred spending his time learning useful information. He didn’t expect that decision to bite him in the ass.
“I’m gonna court him. That’s a big deal to knotheads, right? That should show him I’m serious,” he explained to Kirishima as they sat on opposite sides of his room, just a week ago.
“Well, ya know, typically it’s the alpha that courts an omega,” Eijirou bit his lip when Katsuki glared at him, his fangs sinking in a bit farther than he meant to. “Or beta!! Or another alpha… I mean all dynamics can get together!”
“Just shut up, christ. I know what you meant. Maybe if I was a stupid omega he’d make a move, but he isn’t, so I’m taking matters into my own hands. I just need to get the balls to actually start this shit. The rest should be easy… right?”
“Dude, have you smelled Mido when you’re around him? It’s gonna go perfectly, just you wait! I can already hear wedding bells,” Eijirou sighed wistfully before a pillow smacked him in the face.
“Get out of here, dumbass. I need to strategize.”
In the week after that conversation, Katsuki thought back to the things he and Ei had talked about and moments from his childhood like watching his omega father and the things he would do for his beta mother. Surely an alpha like Deku wanted an omega, so Katsuki just needed to channel that energy.
First, he thought of what Ei said about smelling Izuku. It was weird as hell, but if it’s advice from an alpha, then it’s probably some weird shit he’s just missing by not having instincts like the others.
_________
The two had just finished a sparring session and were sitting side by side on a bench as they caught their breath. They were close, close enough that Katsuki could feel the heat radiating off of Izuku’s sweat-soaked skin.
He reached out, the back of his hand rubbing against Izuku’s arm. Scenting him, just like he saw those extras he called friends do all the time. Izuku gave him an odd look but didn’t question him.
Then Katsuki leaned in, inhaling deeply. He detected a subtle pine scent just barely over the overpowering smell of sweat.
Izuku looked at him with a look of shock.
“What– did you just sniff me?”
“Fuckin’ nasty,” Katsuki gruffs out before standing and making his way to the locker room. He’s halfway through his shower routine when he hears Izuku enter the shower as well.
He rushes through cleaning himself and drying off, getting clean clothes on just before Izuku steps out of the showers with a towel slung around his waist. Katsuki sucks in a breath and flings his workout shirt at Izuku’s head.
Izuku flails but catches it, a look of discomfort on his face.
“Is this– Kacchan didn’t you wear this to spar in?”
Katsuki doesn’t respond, he simply grabs his bag and leaves the room.
Scenting and sharing scented clothing, check.
_________
A staple from his childhood is the image of Katsuki’s father cooking nearly every meal. Masaru would teach him how to properly cut vegetables, how to pinpoint what seasoning was missing from a dish, and even the magic of knowing the perfect leftovers container to use. Omegas like to cook, Katsuki surmised. He can show Izuku just how perfect he could be for the alpha, even if he lacked the instincts.
Every day that week, Katsuki woke up early just to make Izuku breakfast and a bento for lunch. The first morning was a bust: Izuku overslept and missed breakfast and apparently had lunch plans with All Might. Katsuki stared at his two bentos with disappointment.
When he saw the tall alpha in the common room that night, he threatened that he better be downstairs for breakfast in the morning, lest he face Katsuki’s wrath. Izuku looked stunned but nodded in agreement, promising to be awake on time.
He was good on his word, walking into the room just as Katsuki turned off the stove.
“Wow, Kacchan! This smells amazing, where’s everyone else? I was worried I’d be late!”
Katuski looks at him with his brows knit in confusion. Did omegas provide for everyone, not just their alpha? Fuck. Just when really thinks he nails it, a huge oversight flies right over his head.
He quickly tries to cover up the apparent faux pas, “Tch, ‘course they’re late, dumbasses probably stayed up too late, like you usually do.”
Izuku looks at the food and his head turns in a totally not-adorable fashion.
“Kacchan, I don’t think you made enough food for everyone,” Izuku confesses like he’s afraid of offending Katsuki.
“I– it was a new recipe! ‘Serves 10-12 people’ my ass. Good thing those extras were late.” Perfect save. Then he watches Izuku’s eyes fall on the two bentos packed up on the counter. “Told shitty hair he could have it, but he lost the privilege. Congrats on the free lunch.”
Izuku looks… sad. Just for a second. Then he plasters on his thousand-watt smile, thanking Katsuki for all the work he’s put in that morning. He apologizes to Eijirou when he walks into the kitchen a bit later, which earns Katsuki a knowing look.
The rest of the week he invites the shitty extras and makes enough breakfast to feed an army, but if Izuku gets the best of the food and the biggest portions, as well as a bento of “extra food” each day… well, at least no one comments on it.
The ability to provide, check.
_________
All too soon the week is over and Katsuki is nervous. Fuck, he’s actually nervous! He can’t even do that shit where he puffs out his chest and acts overconfident. He’s saved the best—and most nerve-racking—part for last.
A nest. His father always prided himself on his nests, always overflowing with blankets and pillows intricately wound together. Katsuki recalls one time walking into the nesting room and seeing the addition of both his parent's clothing in the mix. He wasn’t invited in that nest, so, he figured it was something couples did. His plan was simple: build the best damn nest the nerd will ever see, complete with both of their clothes so his intentions come across fully.
It took a little bit of finessing to obtain the nerd's clothes over the week, but Katsuki successfully nabbed four t-shirts (each with their own moronic slogan on the chest), a pair of sweatpants, and even a bundle of socks.
He started the nest on the floor, piling on every blanket and pillow he had in a messy lump. He smoothed it out the best he could before weaving in Izuku’s dumb shirts, side by side with his skull tees. He worked in the sweats and socks, along with his own sweaters and undershirts.
Nesting, check.
_________
Their class, of course, had to make a big deal of Izuku’s birthday, keeping everyone hostage in the common room for hours. Katsuki was just thankful those losers managed to grab some beer; it was doing wonders to raise his tolerance for socializing and lower his nerves about his confession.
After enough of dealing with the crowd, Katsuki managed to drag the alpha of his eye away from their peers.
“Kacchan, we should head back to the party, others are gonna notice I’m gone, ya know,” Izuku rambled as they entered the elevator and the doors closed behind them. Katsuki decided to be bold and not drop the hold he had on Izuku’s wrist.
He didn’t humor Izuku with a response. Instead, he just tugged the larger man down the hall towards his room.
“Alright,” he broke his silence when they stood in front of his door. “I’m sure your stupid alpha has figured out what I’ve been doing this last week, but I had to go all out today.”
Katsuki opens the door and drags Izuku inside the room with him. He closes the door behind them and they stand together in the dark for a moment before Katsuki flips on the fairy lights he had previously strung around the room. The lights sparkled in Izuku’s eyes, glittering and shimmering in a way that sucked the air out of Katsuki’s lungs. He seems so entranced with the lights that he doesn’t take notice of the nest. Katsuki huffs and stomps over to his hard work.
Izuku finally looks at him, and then at the nest, and then he seems to… freak out.
“Kacchan! I– what is all this?” His voice is high pitched and his hands fly to cover his face. “Were those my clothes? How did you even get those?”
Katsuki scoffs and rolls his eyes. “Really, that’s what you want to focus on? Is it so surprising that I would make you a nest after I made my intentions clear?”
“Intentions? Kacchan, could you, um, could you tell me what you mean?”
Katsuki crosses his arms, a little upset that he has to go over everything he’s done, but points out all the little things he’s done to show he’s been courting the alpha for the past week.
Izuku laughs.
The fucker laughs at him. Katsuki is about the throw him out of the room and start applying for overseas agencies when Izuku closes the distance between them and envelopes him in a bone-crushing hug.
“Kacchan,” he says with still a hint of a giggle rumbling through his chest, “I’m sorry I didn’t understand. You know, typically it’s the alpha that does the courting. Not to mention, they tell them outright. You should give me a little leeway for not knowing.”
“Yeah, well, it’s not like you’d just start courting a beta like me, so I had to make the first move. And if you have a problem with it, you can forget about accepting my feelings. I can be better than any omega, I’ve shown that, but I’m not gonna be a pushover for you.”
Izuku pushes them apart, his hand traveling to Katsuki’s chin to angle it so that he can make eye contact with him.
“Who says I want an omega?”
Katsuki blinks, his eyes trying to look anywhere that isn’t Izuku, but getting sucked back into green orbs like magnetism.
“I–”
“Kacchan,” the alpha interrupts, “I would be honored to accept your feelings. I feel the same way. I have for a long time. Can I kiss you?”
Katsuki feels his face turn red, his blush reaching the tips of his ears. He gives a slow nod and immediately Izuku’s lips are on his.
The kiss is soft and sweet, and also a little bitter from the beer they had earlier. They both smile into it and Katsuki wonders why he was ever worried at all. They break apart and just look at each other, smiling like a pair of idiots.
Katuski reaches to rub the back of his hand on Izuku’s neck, earning him a confused look from the alpha.
“Kacchan, you did that earlier this week. What are you trying to do?”
“Isn’t it obvious, dumbass? I’m scenting you! Alphas love that shit, right?”
Izuku chuckles and explains how to properly scent, grabbing Katsuki’s arm and nuzzling his cheek into the underside of his wrist. He rubs Ktsuki’s wrist on his neck and his own wrists, before mirroring the actions on the beta.
He closes the distance again with another kiss that Katsuki is much too eager to receive.
“Happy Birthday, nerd.” Katsuki’s voice wavers from the adrenaline as they part once again. “Well, is my nest at least good enough for you to enter, alpha?”
Izuku freezes, his face turning even redder than Katsuki imagined possible.
“Kacchan, do you know the difference between a nest and a heat nest?”