Omegas get so soft when they're getting ready to go into heat, little breast buds perking up, with swollen, puffy nipples. Nothing one would notice over clothes, but Kirishima open-mouth gawks when his best friend pulls his shirt off in the changing room after hero patrol.
"Fuck do you want?" Bakugou snaps.
"I, uh, I just thought you were on blockers, is all."
Kirishima knows how much effort Bakugou puts into being an invisible omega, so this display seems particularly brazen.
"I was. Doc said if I'm on 'em for too long it could make me less fertile in the long run. So I stopped. Got a problem with it?"
"No! No, absolutely not."
Therein lies the problem: the extent to which Kirishima is very suddenly much more than okay with this change.
It doesn't leave his mind the entire train ride home. Bakugou is preoccupied with being fertile? Does that mean he wants a mate one day, wants pups?
When Bakugou calls in sick the entirety of the next week, Kirishima knows exactly why, and he can't stop thinking about it.
Bakugou, all soft and flushed and needy, whimpering in his cushy nest. Would he have a nest? What would it look like?
Would there be someone else there with him? Kirishima gets nauseous at the thought, feels his inner alpha spark up with anger and possessiveness, has to push it out of his mind.
Against his better judgment, he stops by Bakugou's apartment unannounced halfway through the week. He knocks at the door, but there's no answer. He sighs and is about to leave when the door opens.
It's Bakugou's parents.
"Oh, is this a bad time? I know Bakugou's been sick all week, I just wanted to check in on him--"
"No, no, it's not a bad time," Masaru says, and Mitsuki gives him a sharp look. "He's not here though. We can send him your well wishes." Masaru smiles and now Kirishima is even more confused. If Bakugou is in heat, wouldn't he be here, at home where he's most safe and comfortable? Maybe he read the entire situation wrong and Bakugou was actually sick?
"Masaru, don't lie to him," Mitsuki snaps. "Look how concerned he looks now."
"Um--" Kirishima starts, unsure how to proceed. He's met Bakugou's parents a couple times, but he's by no means familiar enough with them to feel comfortable asking what the hell is going on, even though he's panicking a little.
"My son is a problem child," Mitsuki says as she ushers Kirishima into Katsuki's apartment. "We're housesitting while he's in the hospital."
"Hospital!?" Kirishima shouts, and then colors and sits down on Katsuki's sofa. He gets a faint whiff of pheromones as he sits, very unmistakably an omega in heat, very unmistakably Katsuki. It makes his brain feel even more addled. "Sorry for the outburst," he says after he collects himself. "But is he okay?"
Masaru looks towards Mitsuki, and she shrugs. "You're good friends with Katsuki, right?"
"Then I'm gonna tell you this even though I know he'll murder me for it. Katsuki is in the hospital because he has what's known as-- ah, dear, what's the exact term again--?"
Masaru chimes in. "Clinically disruptive heats."
"Right, yeah. Clinically disruptive heats. That's why he's in the hospital. He decided he didn't wanna take his blockers anymore for some idiotic reason and now he's stuck at the hospital until he gets back to normal." Mitsuki shakes her head and sighs.
Kirishima just stares at Katsuki's parents, open-mouthed. Couldn't omegas die from clinically disruptive heats?
"We've dealt with this before, when Katsuki was younger," Masaru continues. "But his blockers managed to control the worst of it."
"Why would he stop taking them, then…?" Kirishima wonders out loud.
Mitsuki rolls her eyes and answers. "Hell if I know. But he was adamant about it."
Kirishima puts his head in his hands and groans. He's heard horror stories about clinically disruptive heats, and the treatment for them is, well, inhumane, even if it's the best that doctors can muster. "Why wouldn't he ask for help?" he asks plaintively.
Mitsuki's answer is matter-of-fact and impossible to argue with. "Because he's my son. He's too proud for that."
Katsuki barely even registers that his father is in the room with him. His own mother isn't even allowed to visit him -- all alphas are barred entry from the heat ward of the hospital -- betas and omegas only. He's in between treatments right now so he's shivering under several blankets, IV pulsing cold into his veins.
The nurses failed to remove the restraints from around his torso and arms and legs after his last treatment, so his movement is limited and he cranes his head to look over at his father, who's brought him some snacks and books.
"How're you feeling?" Masaru asks.
Katsuki lets out a small grunt. He doesn't have the strength to answer, wishes they would pump some fucking sleeping meds into an IV instead of whatever this shit that makes him feel so on-edge is.
"Give and take," the doctor had told him. "Your immune system attacks your body when you go into heat. We need to give you this medication to suppress that response."
His body is freaking out less, although he can barely even tell the difference, because he feels like he's going insane. He's always slightly irritated but these meds are making him feel unhinged , ratcheting the feral omega in him up to near uncontrollable levels.
"Your friend stopped by your place to check on you," Masaru says.
"Red Riot-- uh, Kirishima? The big redheaded alpha? He seemed worried about you."
Katsuki whines, high and long.
"Hey, you okay, Katsuki?"
Katsuki nods, but he can feel his heartbeat speed up at the mention of Kirishima's name. It feels uncontrollable, and it starts to whip him up into a panic. "Kiri--Kirishima--" he whines. "Here?"
"No, no, not here," Masaru says, trying to soothe him. "But he can visit you once you're discharged."
"No," Katsuki says. "No, need him here, please…" he starts to squirm as his body heats up and he's suddenly in pain again. Why the fuck did he choose to come here, why couldn't he just man up and fucking tell Kirishima what was going on?
The monitor next to Katsuki's bed starts to beep as his squirming turns to thrashing. Four beta nurses come rushing in, ushering Masaru out of the room.
He's been through this exact treatment so many times, but it never becomes less detestable to him. It both disgusts him and terrifies him all at once, and his inner omega fights with everything it has to keep it from happening. It's why the restraints don't come off -- it's too hard to get them back on once he gets like this.
The second the first nurse reaches for him he snarls and tries to bite at her hand, his mouth the only available weapon he has left. It takes three of the four of them to hold down his head and strap the breathing mask to it. He's frankly surprised they haven't intubated him yet.
The second the mask fills with synthetic alpha pheromones and he has no choice but to breathe them in he feels violated, like he's going to suffocate. Every breath in sends shock waves of dull panic through his system and he whimpers and his eyes fill with tears as slick gushes down his thighs.
Not like this not like this not like this--
The nurses strip him of his blankets and the rush of chill air over his body makes him cry out.
They're trained to be gentle, but the reality is that twelve-hour shifts of dealing with nothing but half-crazed, feral omegas takes its toll, and Katsuki is more of a pill than most. So they're unceremonious and rough, maybe a little cruel, as they stick him with the instrument meant to simulate an alpha's knot.
It clearly wasn't designed by an omega or for omega comfort. It's cold and stiff and the lube they slather on it makes him numb so he can't even feel anything but a slight, uncomfortable pressure as the instrument slowly inflates and fills him up.
He hates it, Katsuki hates it so much and he's screaming and writhing the entire time it's happening, but he also knows it's the only thing that works, the only thing keeping his body from imploding on itself. So he grits his teeth and bears it for the third time that day, waiting until the pheromones and the instrument have the intended sedative effect and he's too limp and useless to do anything but lie there, half-conscious while the nurses clean him up and put the covers back over him.
He's too far gone to notice that he'd been calling out for Kirishima the entire time.
Kirishima's phone rings just before dawn, early enough that most would still consider it the middle of the night.
He answers the call -- from an unknown number to his personal phone -- hesitantly. He's worried at first that it might be a villain.
"Is this Eijirou Kirishima? I'm calling from Musutafu General Hospital, with regards to a patient we have here."
"Yeah, that's me. What's going on? Is it Katsuki? Is he okay?"
"So you know the patient?"
"What? Yeah, we're best friends. Why?"
"We don't normally put much stock in anything an omega says during treatment, but in this case Bakugou is being insistent. He's...erm...requesting your presence."
Kirishima's heart thumps so intensely he can feel it in his throat.
The doctor continues. "Bakugou is proving rather resistant to treatment this go-around, and I'm calling to request your consent to take part in an experimental treatment."
"What kind of treatment?"
"We only know of two ways to make sure that omegas survive clinically disruptive heats with little to no permanent damage. The first is to spend the heat with their alpha mate -- something about that bond keeps the inflammation in the omega's body from reaching dangerous levels. The other is medical intervention. We typically do not allow alphas anywhere near omegas going through clinically disruptive heats, for obvious reasons, but there is reason to believe that having a trusted alpha in the room while the omega is undergoing treatment may help mitigate distress for both the omega and the medical practitioners administering treatment."
"You mean I'd get to see him?"
"Yes, as soon as you are able to get to the hospital and undergo a briefing on the procedure and your role in it."
"Fuck. Yeah, uh, sorry, excuse me. Yeah. I'm on my way right now."
When they finally let Kirishima into Katsuki's room, Katsuki is asleep, but the scent of distress is palpable and it hits Kirishima like a brick, weighing him down so that walking to Katsuki's side he feels heavy and sluggish.
The room is sterile and bare -- the nurses had moved Katsuki to a new room in a quarantined-off section of the hospital to allow for Kirisihima's presence.
"Is he okay?" Kirishima asks to the doctor who is accompanying him.
"He will be when his heat is over."
That's not comforting in the slightest, but Kirishima is just happy knowing that Katsuki at the very least seems to be medically stable -- he's not on his deathbed, like Kirishima had been picturing.
Kirishima approaches the bed cautiously and sits down in the plastic chair placed next to it. He lets a wave of comforting pheromones wash over Katsuki and after a few moments, Katsuki starts to stir.
The omega opens his eyes and Kirishima can see him sniffing at the air with his nose. The scent trail leads him to turn his head to the side, seeking out Kirishima, and when he notices him his eyes go wide and fill with tears, and he tries to move closer.
Kirishima has to bite his lip and choke back a sob at the pained expression on Katsuki's face. "Hey," he whispers, and then reaches his hand out to find Katsuki's under the pillow. His brows furrow as he realizes that, under the hospital blanket, Katsuki is restrained, thick straps pinning him in place. Katsuki can't do much more than brush against Kirishima's hand with the tips of his fingers.
"Why is he being held down like this," Kirishima says, not bothering to censor the hard edge to his voice. The beta doctor won't be much affected by any scenting he tries to do, so he has to make his displeasure known in other ways.
"It's standard procedure," the doctor says. "Otherwise the omegas are known to hurt themselves, or the nurses."
Bull shit , Kirishima is about to say under his breath, but the monitor next to Katsuki starts beeping. Kirishima turns back to face him and Katsuki is panting, twitching slightly, a soft, pained moan escaping his lips. His eyes are filled with tears and he mouths "help...help me..."
"Well, looks like your presence got him going," the doctor says, smiling as if he and Kirishima are in on the same joke. "The nurses should be here momentarily."
When they show up -- two of them -- Kirishima instinctively grasps Katsuki's hand harder, and the omega's breath hitches. He starts frantically shaking his head back and forth when he sees the nurses approaching him with the face mask.
"What is that for?" Kirishima asks, his voice laced with what would be, to any omega, a tone of command. To the betas in the room it probably comes off as slightly intimidating at best, annoying at worst.
The doctor sighs. "Just let us do our jobs, okay? The only thing we asked you to come here for is your presence, and we don't even need that. So behave ."
Kirishima stifles a growl at being so brazenly condescended to. Doesn't this doctor know who the fuck he and Katsuki are?
He gets a whiff of the mist pouring out of the mask that the nurses are attempting to place on a squirming Katsuki, and Kirishima can't hold back his instinctual response now. It smells disgusting, smells wrong , and his desire to claim, to win, to protect, takes over all of his common sense. He shoots up from his seat and snarls. The nurses flinch but otherwise don't seem too affected, until Kirishima reaches down and grabs the mask from one of their hands and flings it across the room, causing the nebulizer it's attached to to clatter to the floor.
He sees the doctor reach for what is probably a call button, and he puffs up his chest, rage filling him. He flies across the room and barely even registers that he's picked up the doctor by his coat and thrown him against the far wall until he hears the impact. "Get out !" he bellows. "Katsuki is mine!"
The nurses scatter and run out of the door, and he tosses the unconscious doctor out after them and locks the door. He figures plenty of the hospital staff have keys so he overturns a bunch of medical equipment, barricading the door.
He turns to face Katsuki, panting. It still feels like his breath is coming out hot. He centers himself and tries to redirect his pheromones, tries to signal protect instead of fight.
He sees Katsuki shudder a few seconds later, hoping that's a good sign.
The monitor next to him is still beeping all sorts of crazy shit, and he can hear a commotion outside of the room. But he ignores all of that in favor of walking up to Katsuki, taking in his flushed face and teary eyelashes.
"Eijirou," Katsuki whimpers. "Eijirou, please. I need--"
"Shhh," Kirishima says. "You're mine, I've got you, I'll kill anyone who tries to come back in here--"
" Alpha--- "
Kirishima groans, and without a second thought he hardens one of his hands and slices through Katsuki's restraints in a single swipe. He scoops the omega up, letting out a sharp exhale as he feels Katsuki's slick drip onto him. "Shit," Kirishima whispers. "Shit, Katsuki, you're perfect."
Katsuki gets his legs wrapped around Kirishima's waist and starts to rub himself up against him, whining, burying his face into Kirishima's neck.
" Fuck ," Kirishima breathes. "Fuck, okay." He turns around and backs up until he's sitting on the edge of the hospital bed and Katsuki is straddling him.
Katsuki is mindlessly rubbing his cunt against Kirishima, soaking him through his pants. He grabs Katsuki by the scruff of the neck and the omega stills immediately, eyes wide as he waits for his alpha to guide him. Kirishima wants to be naked, to feel his skin press up against Katsuki's, so goddamn bad, but in the frenzy he's in right now the most he can manage is to pull his cock out of his pants and line it up so that Katsuki can easily sink down onto it.
He feels Katsuki's entire body shake as he lowers himself down, can't bite back the groan that it pulls out of him. Kirishima is stunned, Katsuki is so warm and wet and tight, and grinding down so slowly, so deeply on top of him.
"Katsuki, you feel amazi--- hey?" Kirishima pauses, noticing that Katsuki's face still seems hot and flushed in the bad way, not the good way. "Katsuki, look at me."
Katsuki does, and his eyes are unfocused, his brows furrowed like he's in pain. "Help--" he says again, going limp in Kirishima's lap.
The pounding on the door outside is getting louder, and Kirishima thinks he can hear them trying to push their way in. He's fucking stupid, he realizes. The only way Katsuki can get through a heat with the condition he has is with this hospital's treatments; Kirishima doesn't cut it, he's not Katsuki's mate and that's the only other thing that could ever--
"Please," Katsuki whines. "Please, you gotta--"
Kirishima quirks his eyebrow and looks up at Katsuki, drawn out of his own head by the ever-present edge of attitude in Katsuki's voice, even in the midst of a clinically disruptive heat. Kirishima is about to ask "I gotta what?" but when he looks up he doesn't need to ask the question anymore, because Katsuki's head is turned just slightly to the side, his neck on display, an offering. Kirishima doesn't even think about it, he just leans down and sinks his teeth in deep.
Katsuki has never had an enjoyable heat. Desire has always been dangerous for him, because of his condition, any search for pleasure likely to end up with him in an emergency room.
The blockers had done away with all of it, and he was grateful. He had needed it to make it through high school, to be as successful a hero as he had become.
Was he jealous of everyone he knew who got to boast of their stupid, normal, feel-good heats? Of course he was. But he would never say that. In the end he envied them more that they got to decide what to do with their bodies when it came down to it -- they weren't limited to just a few inflexible options. Take blockers and feel nothing, feel less than a beta feels, don't take them and resign himself to the fucking hospital everytime he went into heat, retraumatizing himself, or find a mate and blindly rely on them to keep him alive and well during heats until the end of his days.
There would never be an easy option for him.
But Jesus Christ does Kirishima feel amazing.
When Kirishima's teeth clamp down on Katsuki's neck, a wave of pure pleasure surges through him, but it doesn't stop, it just keeps coming , relentless, but not relentless like it was before, not an empty, painful, burning need, no pain at all, just a prickling of pleasure from his neck down to his groin.
Real pleasure, actual release. He doesn't care that he's crying into Kirishima's shoulder as he grinds down into him, nothing has ever felt this good before and there's no way he's stopping just because of a few stupid tears. Let them fucking fall.
Kirishima's teeth stay glued to Katsuki's neck, and objectively Katsuki can feel that it's supposedly painful, but it's also transcendent . Kirishima's nails dig into Katsuki's waist, pushing him, down, down deeper, and he feels Kirishima start to swell at the base, feels his knot start to catch.
" Fuck ," he groans, no longer an enfeebled whine but now his own voice, strong and defiant. "Fuck, Eijirou, want your knot. Give it to me ," he demands, his voice a low growl, and Kirishima lets out a gasp, hips jolting up. His tongue returns to the fresh wound on Katsuki's neck as Katsuki feels his body tremble, hears him curse under his breath and moan as his hips stutter and his knot gets caught deep inside of Katsuki. Katsuki groans at the fullness of it, sighing and then pawing at Kirishima's chest until the alpha gets the hint and leans back, until they're lying down and Katsuki can rest his head on Kirishima's chest and splay his legs out to the sides.
This is how the hospital staff -- and Katsuki's parents, to Kirishima's complete and utter embarrassment -- find them. Katsuki asleep, blissed out of his mind in a deep restorative slumber, and Kirishima, coming down from his high, knot slowly deflating inside of Katsuki.
He apologizes profusely, now back to his usual polite and upbeat self, and offers to pay for any equipment that he'd broken. The doctor tells him that they were about to get someone with the appropriate quirk to blast through the doors and barricade when one of the nurses noticed that Katsuki's vitals -- which they could see remotely -- had returned to stable numbers. And, well, now they all knew why.
They want to keep Katsuki for one more day to monitor his symptoms, but assure a very suddenly surly Kirishima that he will be able to stay with him, in a private ward. After that, Katsuki will be free to spend the rest of his heat in his own home, with Kirishima.
Kirishima makes sure that this is what Katsuki actually wants when he wakes up, makes sure this isn't just some sort of fluke.
"Are you fucking stupid?" Katsuki says, but his voice is soft. "Obviously it's what I want. I'm fucking kicking myself that I didn't tell you sooner. Could've avoided this entire shitty hospital stay."
Kirishima grins and pulls Katsuki closer to him in their now-shared hospital bed. Katsuki grumbles but doesn't protest to being cuddled.
"One more question?" Kirishima asks, hesitantly, and Katsuki looks up and nods.
"Why'd you go off your blockers if it's so dangerous for you?"
"I fuckin' told you why. Don't wanna risk not being fertile."
Kirishima blushes. "So you…"
Katsuki turns his head to the side, Kirishima thinks because he's probably blushing too. "Yeah," he whispers. "One day."
Kirishima squeezes Katsuki tight and basks in the promise of their new future together.