Work Text:
Izuku squirmed in his seat as he rode the train back to his apartment. He was nearing his heat and was regretting making the trip out to work this morning. Sure once he had worked the big 3 inches wide, 8 inches long knotting dildo inside of him it had staved off the worst of his arousal but rocking against a silicon knot all day could only do much.
Kaminari offered him a quickie during lunch but Izuku had been called off to an emergency crime scene before he got the chance to remove his underwear and bend over the kitchenette counter and he was left feeling unsatisfied the rest of the day.
A sudden lurch in the train caused the dildo in his hole to rub against his prostate and he mewled at the feeling. He couldn’t wait to get back home to his nest and fuck himself on his other, bigger dildos. To stave off some of the arousal he felt, Izuku cupped his small cock through his tight leggings and began rubbing himself.
No one minded him as he rocked himself into his palm. It took just another lurch of the train and Izuku was coming into his underwear, adding to the wetness he had already acquired from his slick ass.
Unfortunately for Izuku, a single orgasm wasn’t enough to quell the feeling of need in his groin and lower stomach. It really only added to flame growing inside him. Izuku brought his hand down to rub himself off again and he was moaning when the guy next to him whistled. He flushed at the attention but continued his work.
“You should just drop your stupid pants and fuck yourself, Omega,” the man said. Izuku whined at the words and squeezed his cock through his pants. He continued the rhythmic motion as he felt the man lean closer to him. “Pull your tiny cock out, Omega, let’s see it.” Izuku shivered at the words - it was clear this man was an Alpha from his tone. He brought a thumb up over his waistband and pulled it just far down enough for his cock to hang over the waistband. Like most omegas, his cock was a mere 3 inches long and was more than small enough to fit in his entire hand. Izuku wrapped his fingers around his aching cock and watched his entire length disappear before he gave himself a squeeze and whimpered.
“Good boy,” the man said.
At his words, Izuku finally looked up at the Alpha who had been addressing him. He was met with vibrant red eyes and pale blond hair spiked up around his head. The alpha had a broad, muscular body and was clearly a few inches taller than him. Izuku also noted a substantial bulge in the man’s black jeans.
An image of fellow pro hero Dynamite passed through his mind but it was quickly forgotten when the man cocked his eyebrow at Izuku and he realized he had stopped playing himself. He gripped his cock tighter and began working himself in his hand again. The feeling was intensified knowing that a strong alpha was watching him get himself off on the train and he rocked his hips hoping to get friction inside of himself.
The alpha leaned into his space and wrapped an arm around Izuku. Izuku’s strokes faltered but the alpha murmured “Keep going, Omega,” so Izuku continued to pump himself in his hand. The alpha reached under Izuku’s thigh and began scooting him into his lap. Izuku aided him by lifting his right leg up over the alpha’s left so that it was either for the alpha to slide him into place over his thighs.
“You’re such an obedient omega. All pliant while you’re in heat,” the man said as he brought his hands down to Izuku’s thighs and splayed him open. Izuku’s eyes flickered up and noticed a few other alphas and some betas watching their show, stroking themselves. The alpha behind him tutted, “Keep your fucking focus on me, Omega.”
Izuku tore his eyes away from the audience and whined when the alpha encircled his hand with his own bigger one. “Gonna make you come on my knot, Omega,” the alpha said as he began guiding Izuku’s strokes. “My name is Katsuki Bakugou in case you need a name to moan.”
The hand encasing his own was hot and calloused. It felt amazing against Izuku’s small, soft one. Katsuki was expertly guiding his hand up and down and squeezing every now and then. The pressure began to build up once again and Izuku couldn’t resist rocking his ass back against Katsuki’s crotch. The movement caused Izuku to moan when the dildo hit his prostate and Katsuki cursed. “You’re such a needy little shit,” he said.
“Please, Alpha,” Izuku whimpered. “Please let me come.” Izuku was rutting quickly against Katsuki’s swelling cock.
“Fuck,” Katsuki groaned tightening his hold on Izuku’s cock. “Come for me then,” he said.
Izuku tipped his head back in pleasure as he released his watery spunk into his and Katsuki’s hand and his ass gushed with more slick, wetting Katsuki’s jeans. “You’re such a slut,” Katsuki said, maintaining his hold over Izuku’s hand and his cock. Izuku whimpered at the feeling of overstimulation but his cock was getting hard again and his asshole was clenching around the dildo. “You’re gonna have to come again while riding my cock,” Katsuki said.
The hand over his cock and hand finally released him and Izuku was able to unclench his own fingers. He stretched out his hand and noted the way the cum was drying in sticky patches over his palm. It was pretty gross.
He didn’t have time to dwell on it though as he was pushed up from Katsuki’s lap. He stood on shaky legs, eyeing warily at the few people still jacking off to him. He looked over his shoulder and found Katsuki working his zipper open and taking his big cock out. Izuku’s mouth watered at the girth and length - it was definitely bigger than the dildo he had inside.
After Katsuki got himself out, he reached forward and pulled Izuku’s leggings the rest of the way down over his ass revealing slickened ass cheeks and a dripping hole with a dildo pushed deep inside it. Katsuki began massaging his ass cheeks as Izuku continued to stand. “You fucking slut. Omegas should know better than to leave the house in heat,” Katsuki offhandedly said while spreading Izuku’s cheeks. “Even got a fat dildo in ya,” he commented as he took the base of the dildo in his hand and pressed it deeper inside Izuku.
“Please, Katsuki,” Izuku moaned. “Want your knot.”
Katsuki smirked as he began fucking Izuku with the dildo. “Bet you do, Omega. I’m gonna keep playing with you just a bit,” he said.
The dildo was ruthless as Katsuki pulled it out and thrust it back in with malice. The knot burned every time it was forced out of Izuku’s quickly loosening hole and it hit his prostate every time it was pushed back in. Katsuki continued relentlessly fucking Izuku with the dildo until Izuku felt like he would come again - this time without touching his leaking cock.
Eventually, Katsuki removed the dildo and placed it on the seat next to them. Instead of bringing Izuku down to his cock as he expected, Katsuki leaned forward, spreading Izuku’s ass, and began lapping at his gushing hole. Katsuki was an expert at licking up Izuku’s slick; his tongue circled the hole, toying at the wrinkled flesh before it began probing in and truly fucking him open. Izuku cried out and he braced his hands on his thighs so he wouldn’t fall face first onto the train floor.
Katsuki continued his assault on Izuku’s hole as the train doors opened. The previous people who had taken a seat in front of them exited the train and a new wave of people took their place. A beta sat directly in front of Izuku and immediately took himself in his hand and began jacking off. Izuku squeezed his eyes shut to the scene and focused on the feeling of Katsuki behind him.
Katsuki’s tongue probed around the wet hole for a little longer before he retracted his tongue and placed a final kiss on Izuku’s winking hole. “K, Omega. It’s time for my knot,” he said, gripping Izuku’s waist. Izuku whined in his grasp and wiggled his ass. Katsuki’s eyes landed on the beta jacking off and smirked. “You put on a good show, Omega,” he said.
The grip on his hips tightened as Katsuki pulled him down to his cock. “Gonna fuck you and breed you,” he gritted as he guided his cock into Izuku’s sloppy hole.
“Alpha, please. Want your pups,” Izuku cried as his ass was stretched open around Katsuki. Katsuki must have been almost 4 inches in width for the stretch to feel so intense. Izuku couldn't help but fantasize about just how big his knot would be.
“You’re so fucking tight,” Katsuki groaned as he pushed Izuku further down his length. “Thought your asshole would be loose as fuck now,” he said, more to himself.
When he finally bottomed out, both Izuku and Katsuki moaned. As soon as his cock was all the way in, Katsuki didn’t hesitate to readjust his hold on Izuku and begin his fast paced thrusting. Izuku yelped as his ass was stretched impossibly wide over Katsuki’s cock. The stretch and pain were immense as he was used as cock sleeve for Katsuki’s pleasure. Katsuki paid no mind to Izuku as tears began pooling in his eyes. Katsuki kept his grip firm as he bounced Izuku in his lap.
“Fucking slut,” Katsuki growled and Izuku’s hole tightened at the words. “You’re fucking gagging for my come,” he said, slamming Izuku down harder.
“Yes, Alpha. Please fill me up, want your pups,” Izuku moaned while being aggressively handled. Izuku knew that there would be bruises from where Katsuki was gripping his waist.
Katsuki continued his punishing pace and against Izuku. On one particular stroke, he brushed against Izuku’s prostate making his ass clench down around the cock as he rode out his third orgasm with a cry. Barely any cum leaked out of Izuku’s cock at that point. His erection wavered but Katsuki adjusted their positions so every thrust hit Izuku’s prostate and he remained hard against his stomach.
“You’re gonna come again around my knot,” Katsuki said as an order rather than a question.
Izuku nodded, “Yes, yes, gonna come on your fat knot.” There were tears now flowing down his cheeks from pleasure as he was continuously used. Katsuki snaked a hand around and started pumping Izuku’s cock again as his knot filled in rapidly. “Knot me, Alpha. Breed me,” Izuku cried.
The knot began catching on Izuku’s entrance as Katsuki’s thrusts became sloppy. He continued fucking Izuku with shallow thrusts and jerking Izuku off in his hand until his knot fully expanded and caught inside Izuku’s hole. “Omega,” Katsuki groaned as he began releasing thick ropes of come inside of Izuku’s hole. Izuku moaned at the feeling of warm come flooding his intestines.
Katsuki’s release continued while he stroked Izuku’s cock in earnest. He twisted his hand around Izuku’s small cock as his thumb worked over the weeping red head. Izuku felt his insides spasm and he wailed “Katsuki!” as he came for the fourth and final time. His muscles clenched around Katsuki, finishing off milking his cum and he finally slumped back into Katsuki’s arms.
Strong arms wrapped around Izuku as his ass twitched in aftershocks around the knot buried inside him. “Your ass is taking my knot so well, Omega,” Katsuki noted, then he began sucking at the delicate skin around Izuku’s throat and his mating gland. Izuku whined at his touch but ultimately let Katsuki suck deep purple marks into his skin.
“Izuku,” Izuku stuttered out while Katsuki licked at his work.
“What?” he asked.
“My name’s Izuku.”
Katsuki began sucking and biting his shoulder. “G’d to know,” he said, thrusting up into Izuku again. Izuku whimpered as the knot rubbed against his prostate.
Katsuki continued his lazy thrusts into Izuku while nipping at his shoulders, back, neck and jaw. “You’re pretty as fuck,” he commented, “and you have a nice ass.” Izuku let Katsuki use him and he closed his eyes, riding out the sated feeling he felt. This encounter would only accelerate his heat but for now, he felt good and laid his head back as Katsuki continued worshipping him.
The train stopped again and the doors opened to another wave of passengers. This time no one sat in front of the pair since there wasn’t much of a show left.
When Katsuki’s knot went down, Izuku shifted in Katsuki’s lap and whined as cum leaked out of his loose ass until Katsuki brought his fingers into Izuku’s mouth and began thrusting them against his tongue.
It was then that Izuku opened his eyes and noticed he missed his stop and he let out a groan. Katsuki noticed as he continued fucking his fingers lazily into Izuku’s mouth. “It’s okay, Izuku. We’ll take the train back. You can warm my cock until we get to your stop and then I’ll take you home and fuck you into your bed until you’re filled with my pups. How does that sound?” Izuku moaned around the fingers and nodded his head. “Good, Omega.”