Work Text:
It was just a normal day for Katsuki. In the morning he woke up, ate breakfast, did some working out, and went to work. Agency wasn’t too far from his home so he was walking there. During his patrol he kicked asses of few villains, that where stupid enough to resist arrest. Nothing extraordinary.
Rest of the day he spent behind his desk doing paperwork, and when he got back home, he was already pretty tired. Quick dinner and shower, and he was ready to go to bed. Some people were telling him that he was a workaholic, that it wasn’t good for his health, but he was satisfied with his lifestyle.
He covered himself with a blanket and was looking forward to some hours of deserved sleep. But he wasn’t going to get them. He could be asleep for no more than an hour, when he was woken up by voices. One of them was almost shouting. “... the hell? … Shitty Nerd … fix it!” Door slammed. Why did the person sound like him?
Wait. There were people in his bedroom! He opened eyes and sat up, only to realize that he wasn’t in his bed anymore. He was on the ground in some weird looking room. One wall was completely covered by bookshelves and furniture looked medieval. On the other side was a fireplace, from which was coming pleasant heat.
When he looked under himself, he saw a pattern on the floor surrounded by lightened candles and dried flowers. He could smell something in the air, but couldn’t figure out what it was. It wasn't from candles or flowers for sure. Not even fire. It was smokey but still somehow sweet. He liked it.
Then he finally noticed the one person, that didn’t leave the room, looking down at him. He looked exactly like him except from horns coming from his forehead, wings on his back and tattoo on his arm. He was dressed only in pants, high boots and a red cape with fur.
“Oh shit, you’re awake.” The person said with a grin. Yeah, he totally sounded like him. “Who are you fucker?!” Katsuki’s head hurt and when he tried to stand his vision got blurry for a few seconds. The other came to him and helped him get up on his feet. The smell got stronger as he was near.
“We are probably the same person, just from different worlds. Deku wanted to try some spell from stupid book he found in ruins and need some enough magically potential blood, and this is a result.” Katsuki groaned. So he is paying with his precious sleep hours for the curiosity of Deku that wasn’t even from his world. Looked like he was the same everywhere. Just a nerd.
He would hope that it was all just a dream, but it felt too real and even pinching himself didn’t help. Deku still wasn’t going, so they talked a little bit. About their worlds, the differences. He learned that here they didn’t have quirks but magic and his other self was dragon shifter, which was pretty awesome.
Meanwhile they also agreed that Katsuki will call the other Bakugou, so it won’t be more weird than it already was. “Hey, what is that smell?” He finally asked, because it was still bothering him. “Just my rut is near.” Bakugou shrugged like if it was nothing, going to stand at the fireplace.
Katsuki turned his head to the side. What did he mean by rut? Bakugou must have noticed his confusion, because he started laughing. “You don’t know what a rut is? And I thought you smelled like omega.” He went back to him and put hand on Katsuki’s waist, running them up to his pecs then down to his hips, and back on his waist.
“Even your body is like omega’s.” He slowly licked his lips, which made Katsuki nervous. But when he tried to step away, Bakugou didn’t let him. “Deku probably won’t be back any time soon.” He purred and gave a long hot lick to Katsuki’s neck, making him shiver. He was still a little bit disappointed in the lack of scent gland.
Katsuki wanted to fight it, push him away, but he couldn’t. Something back in his mind kept telling him to stay and who knows why he decided to listen to it. He let his body relax under touches. He didn’t protest when he was kissed and even when he was maneuvered to lay down on furs in front of the fireplace. Katsuki wasn't a virgin, but although he was bi, he never slept with a man before. Who could know, the first time would be with… well, himself.
But every light touch and kiss felt too good to stop. It didn’t take long before they were both naked and he could just stare. Katsuki never was insecure about his length, he was even above average, but the guy was just huge! Katsuki gulped, just imagining this monstrosity in his guts.
He couldn’t decide if he was more scared or excited about it. Bakugou didn’t waste time and got him on his knees and hand, presenting ass high in the air. Katsuki was dry, no slick to see, but it was nothing that some Deku’s shit wouldn’t fix. In one of his drawers there must be some kind of oil and sure it was. With his catch he could get back on the furs.
Katsuki moaned when first slocked finger entered his hole. He fingered himself most of the time when he masturbated, but it was so much better when someone else was doing it. Number of fingers stretching him wide was getting higher and he started to have problems taking them.
“Too much!” He managed to get from himself between all the moans and whines. His cock was leaking precum all over his lower belly. “You need to withstand it if you don’t want to tear later.” Bakugou warned him. Kissing and biting the back of Katsuki’s neck.
He was satisfied only when all five fingers were sliding inside without resistance and took them down. After he poured more oil in the gaping hole and over his own cock, he kneeled right behind Katsuki, rubbing over the globes of his ass. He just has to slap him. Sound coming from Katsuki was somewhat between scream and moan.
Normally he would complain, but now the act made him even hornier. “Please, Bakugou.” He begged. Sudden emptiness hurt him more than the stretching. “It's Alpha for you, Omega” He could hear chuckle behind him, before he felt hot cockheat on his hole.
It was still big for him and Bakugou had to give a good push to get it inside, but then he could continually sink it in. Katsuki was openly crying when it was finally all inside. “Alpha!” He moaned. None of his toys ever made him feel full this much. It hurt so badly, but also was constantly pressing against his prostate. And then when it started moving.
Bakugou was panting behind him, hands around Katsuki’s waist as he was thrusting inside. His wings stretched and contracted with every move. He felt like his rut was taking all over him, not letting him think about anything else than breeding that ass in front of him.
Katsuki felt that he was getting close to his release, when he felt something weird pressing to his hole. “What - What is it?” He asked shakily. With every thrust it was trying to get inside, stretching him almost impossibly. “You will take my knot like a good omega.” Bakugou bit his shoulder and pushed even harder.
Katsuki’s eyes widened at the word knot. Something he knew just from dogs. He panicked, thinking that it had no chance fit inside of him. He tried to move forwards, but Bakugou held him too tightly. Katsuki’s was opening more and more, but it still wasn’t enough.
When he thought that he would tear for sure, the knot finally went through and caught on his rim. Pressure on his prostate was too much and he came untouched, painting white fur under him. He didn’t have time to catch his breath, when Bakugou started cumming.
Load after load was entering him, filling to the brim. Knot prevented any of the liquid from getting outside and Katsuki could swear that it was making his belly swell. Stream in his guts didn’t stop even when they laid down. Bakugou was hugging him from behind, praising him for being such a good omega for him.
Katsuki was getting tired. Warm coming from the body behind him and cum inside him was luring him into sleep. When he woke up the next day, he thought it was all just a really weird dream, but the puddle of the cum under him was telling otherwise. He fell back into his sheets realizing that he got fucked by himself, that wasn’t even normal human, and he fucking enjoyed it! At least it was Saturday, he couldn’t imagine spending the whole day of patrolling with cum dripping from his ass.