Katsuki obviously couldn't go to the infirmary when Izuku was going into heat. It would reveal Izuku's second gender to whoever was the nurse.

He thought about going to the changing room but he didn't know when the other students would come back, it was dangerous. Moreover, Izuku's arousing scent would stay in the room and alert people of what had happened.

So, Katsuki decided to go to the dorms. All the rooms were scent-proofed and could be locked. It was the perfect option.

"Alpha..." Izuku let out a small whimper as Katsuki laid him on the bed. The omega was now completely in heat, all of his rationality already long gone. Only his omegan instincts were left, the intense urge to mate deeply overwhelming him. "It hurts..." He whined when another burning wave of his heat took over him.

"Shh. I know, kitten." Katsuki soothed Izuku in a gentle voice. "I'll help you. Let's remove your hero costume first." He said as he began to take Izuku's clothes off before they got soaked with the omega's slick.

Izuku's arousing pheromones were quickly spreading inside the room. The irresistible scent smelt absolutely delicious and Katsuki had to use all of his self control to not succumb to it. It was in moments like these he was especially grateful to be a dominant alpha, it gave him more control over his instincts.

However, even if Katsuki had already seen Izuku in heat several times, nothing could possibly make him resist the sight of the omega dripping wet with slick. It was so arousing and always turned him on to no end. Izuku's slick had a special scent, close to the smell of cinnamon roll and vanilla. It drove the alpha absolutely insane.

Katsuki let out a low growl as he tried hard to stay calm. His cock was already hard and pulsing inside his boxers. The irresistible scent Izuku was releasing and the small, adorable whimpers the omega was letting out weren't making his raging erection any better either.

"Alpha..." Izuku called between small moans. He always referred to Katsuki by using alpha when he was in heat. It was the sign he wasn't thinking straight anymore and instead thought with his omegan instincts.

"Want you..." He whimpered, the omega seductively crawling to Katsuki and reaching out to the alpha's pants.

"Don't do this." Katsuki immediately stopped Izuku. As much as he wanted to pull his cock out of its restraints and bury it deep inside Izuku, fucking the omega hard, he wouldn't do it. He couldn't do it. It would be taking advantage of the omega's state and Katsuki refused to betray the trust Izuku had in him.

"Need you..!" Izuku let out a needful whine. The omega was upset Katsuki had stopped him to do what he wanted so he tried again to reach Katsuki's clothed erection, only for his wrists to be tightly grabbed by the alpha this time.

"I said no." Katsuki firmly stated. He was used to deal with Izuku's in heat and knew he needed to be firm, or Izuku would never try to stop to mate with him.

But Izuku suddenly let out a sad whimper. "Why? Am I a bad omega?" The omega sniffled in a small, heartbreaking voice; the look of sorrow and painful rejection inside his emerald eyes making Katsuki's heart ache.

"No, you're not-" Katsuki immediately began to say but Izuku let out another heart-wrenching sob. "Alpha doesn't want me?" He whimpered, tears starting to fill his beautiful green eyes.

Katsuki couldn't resist anymore.

He suddenly pinned Izuku to the bed, his body on top of the tiny omega and caging him against the mattress, before speaking out in a low, husky voice. "Believe me, you have no fucking idea how bad I want you." He rasped out.

He didn't need Izuku to seduce him to already want to fuck him. The omega was so beautiful and sexy Katsuki thought he would lose his control at any instant.

"You're so pretty, kitten." Katsuki murmured in a breathless voice. "Such an adorable omega..." He praised, knowing Izuku loved to hear any compliment when he was in heat.

It didn't fail as Izuku immediately started to purr, a low rumble forming inside the omega's chest. His sadness just second ago was already forgotten, the only thing that mattered now being the fact that Katsuki wanted him...

"But we can't." Katsuki suddenly stated. "I'll only use my fingers." He firmly declared.

His words instantly got Izuku mad again; the omega starting to squirm to free his wrists from Katsuki's grasp. "No. Not fingers! I want alpha's!" He loudly whined and shouted.

Katsuki ignored Izuku's scream as he held the omega's two wrists in only one hand, using his other hand to spread Izuku's legs. He reached the omega's entrance and circled his fingers around it, coating his digits with slick.

"No-!" Izuku continued to protest when Katsuki suddenly sank two fingers inside him.

"Ngh!" The omega instantly moaned at the action. His back arched up and his head fell back on the bed. He immediately stopped to thrash around and began to loudly whimper as Katsuki started to finger him, his pink lips parting to let escape beautiful mewls.

"Ahh! Alpha!" He loudly moaned when Katsuki perfectly hit his prostate.

"Feels good, kitten?" Katsuki lowly asked, the alpha's crimson eyes not leaving Izuku's face for any second. He loved the sight of Izuku's flushed expression when he was pleasuring him. The omega's cheeks were covered with a dark blush while his beautiful emerald eyes looked half-lidded in bliss. It truly was breathtaking to watch.

"Yes! Feels good!" Izuku answered between irresistible whimpers. He was already lost in lust and couldn't think about anything else than the pleasure Katsuki was making him feel anymore. He quivered in delight underneath the alpha, his arousing pheromones spreading more and more in the room.

"Fuck. You smell so good." Katsuki husked out as he took a deep breath of Izuku's scent. The delicious smell was making his head spin, but not as much as the feeling of Izuku's soft walls twitching around his fingers. "You're so warm and tight, it's driving me crazy." He said with a low, possessive growl.

The sound triggered flutters to erupt inside Izuku's stomach. The omega moaned, his whole body shuddering as his orgasm got nearer. He could feel he was getting close and only needed a little more stimulation to reach his climax. "Alpha! More!" He whimpered between adorable mewls.

"Fuck." Katsuki cursed under his breath. The alpha couldn't possibly resist anymore and he suddenly pulled his fingers out of Izuku before reaching for his own pants. He quickly opened them and finally took his hardened cock out of his boxers, his thick dick throbbing and pulsing in his hand.

"I'll do it like this." He husked out just before leaning and taking both his and Izuku's member inside his large hand.

He used Izuku's slick as lube as he began to eagerly stroke them together, the sensation of their cock rubbing against each other being pure bliss for both of them. Katsuki jerked them off fast and hard, the alpha wanting to push Izuku and himself over the edge.

"Ahh! Ngh!!" Izuku kept loudly moaning as Katsuki kept increasing the pace of his stroking more and more. The omega was losing his mind in pleasure. His whole body was quivering and trembling in delight. Warmth was building up inside his stomach and threatening to burst any second now. Precum was already dripping from his swollen tip.

Katsuki let out a particularly deep growl right next to Izuku's ear as he bucked his hips hard, and it was enough to suddenly trigger Izuku's orgasm. "Ngwhh!" The omega lewdly moaned as he came. His entire being shook and his back arched up, white milky cum shooting on his belly and tainting his soft, pale skin.

Katsuki came not long after. The alpha loudly growled as he reached his climax, his cum shooting from his cock and also landing on Izuku's stomach. He kept stroking their dick together a few last time, milking them both dry, before finally stopping to move his hand.

"Fuck, that was intense." He breathlessly husked out. His respiration was coming out in harsh pants and sweat was surely glistening on his forehead. He looked at Izuku and found him halfway passed out, the omega fighting to keep his beautiful emerald eyes opened.

It was normal. Izuku always was completely exhausted after orgasming during his heat. He would stay half-asleep a few minutes at most before finally coming back to his senses, any signs of his heat magically gone.

Katsuki looked for something to clean the mess they had made. He found some tissue and started to wipe away the cum on Izuku's belly. He then used a wet towel to clean the omega's body from any slick or sweat covering his soft skin.

That's when Izuku slowly started to wake up. "Kacchan..?" The omega sleepily called, his mind still groggy. As usual, he didn't remember what had happened during his heat. Only small glimpses of it were appearing inside his memory.

"Hey. I'm here." Katsuki said as he gently removed one sweaty green lock from Izuku's face. "How are you feeling?" He asked.

"Fine..." Izuku timidly answered with a soft blush on his cheeks. Even if he didn't remember what had happened, he still felt shy and slightly embarrassed. "Thank you, Kacchan..." He timidly murmured.

"Don't worry about it, Deku." Katsuki replied. The alpha really didn't mind helping Izuku with his heat if it meant keeping the omega safe. He would always do it without any hesitation.

"We should go see if the others extras have came back." He then said as he stood up.

They had already raised enough suspicion as it was and should probably be extremely careful during at least the next few days...

Hope you liked this smutty chapter, don't forget to vote or comment! :)