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“Do you think Kacchan is pregnant...?” Izuku asks his friends, and their varying reactions throw him for a loop.
Tenya chokes on his drink, pounding on his chest to get his breath back. All breath seems to have left Ochako, but for a different reason as she tries not to laugh. It's not successful, but Shouto's blank stare might be the most unnerving of all.
Izuku's brows furrow. “What?”
Once Tenya can breath properly again, he clears his throat and chops his hand through the air in a familiar motion. “Midoriya-kun, didn't you have sex education at your middle school before attending UA...?” he asks carefully. “It's a require curriculum for alphas and omegas, after all!”
“Uhhh...” Izuku says, scratching the side of his face. “I had presented as a beta before UA. I hadn't known I was an alpha until...pretty late into UA, and well, those classes hadn't been a priority anymore.”
Their second and third years didn't leave much room for anything but surviving the world wrought by the war. Izuku had gotten suppressants when his alpha characteristics started to make themselves known. It's actually Katsuki who had figured it out first, and with All Might, the three of them determined it was because of One For All.
Tenya seems visibly upset by the news, but before he can go on a tangent, Ochako puts her arm out to stop him. “Deku-kun, this is serious,” she says quickly as Tenya deflates beside her, unable to give an impromptu sex ed class in the middle of a cafe. “You're an alpha in a serious relationship with an omega. You can't expect Bakugou-kun to handle all the safe sex precautions!”
Izuku really wishes he hadn't said anything at all as his face heats up, and he's sure he looks like a strawberry with a red face covered in freckles and unruly green hair. “That's not-! We practice safe sex, and I'm careful, I swear! We never knot without condoms during a heat, if he even lets me knot him then at all!”
“That's more than I thought I'd learn about Bakugou-kun this morning,” Ochako murmurs as she slumps back in her seat.
“...do you knot him outside of heats?” Shouto questions as Tenya and Ochako flail in unison, trying to signal Shouto to stop.
“Todoroki-kun, you don't ask those kinda things in public!” Ochako hisses, face much pinker than usual.
Shouto tilts his head, keeping eye contact with a flustered Izuku. “It's an important question,” he points out.
“Yes...?” Izuku replies as he sees Shouto's eyes widen. “What? It's not like a bad thing! Why are you looking at me like that?”
“...do you bother with condoms?”
Izuku scrunches his face. “No, why would we outside of heats?”
The table falls silent, and Izuku can feel his heart trying to beat out of his chest and his stomach attempting to fall to the floor. He watches his three closest friends share matching concerned looks. It's not an uncommon thing with them, but since this isn't just about Izuku's self-sacrificial tendencies, Izuku's more worried than he would usually be.
“Get him a pregnancy test,” they all say in unison, and Izuku feels his life flash before his eyes.
Handing Katsuki a pregnancy test goes as well as Izuku thought it would. He manages to catch the box thrown back at his face, but it means Izuku doesn't have time to prepare for the his favorite All Might statuette flying at him. It smacks him on the shoulder before tumbling the ground, only a bit banged up.
Izuku makes a choked sound, and he has to make a choice between All Might and Katsuki. With his boyfriend already halfway out of the room, Izuku ignores his possibly broken figurine and chases after Katsuki. He gets the bathroom door slammed in his face for his troubles as Izuku hears Katsuki heaving into the toilet.
“Kacchan, are you okay...?” Izuku asks through the locked door.
After another minute of retching, Izuku hears the toilet flush. He doesn't expect the door to slam open quite so soon, smacking him in the fact. Izuku holds his nose in quiet pain as he locks eyes with Katsuki. His boyfriend shows absolutely no remorse, holds his hand out expectantly.
“Hand it over,” Katsuki demands, his tone even and his face pallid. “Now!”
Izuku fumbles, hands the box to Katsuki, and doesn't get to say anything in response before the bathroom door slam behind Katsuki, again. With an uneasy exhale of breath, Izuku settles himself next to the door, waiting for whatever comes next. It's a nerve wracking ten minutes, the longest of Izuku's life, if he's to be honest.
The door bangs open again, and Izuku's glad he decided to sit where the door doesn't open, because he's sure there's some cracked plaster behind that door right now. “Kacchan...?” he asks as Katsuki pulls him to his feet then slams him back against the wall. “Kacchan-! What-”
“You and your fucking super sperm!” Katsuki curses, waving the pregnancy test around in his free hand. “The likelihood of getting knocked up outside of heats is almost fucking zero! How the fuck did you manage this shit!?”
Izuku blinks as he processes this new information. “That's not fair!” he protests under Katsuki's glare. “You like being knotted and-”
“Nope, our fucking kinks aren't the problem, damn nerd!” Katsuki interrupts, his face turning a shade of pink Izuku quite enjoys to see on him. “Stop smiling! This isn't funny!”
“I didn't say it was!” Izuku replies as Katsuki slams his back against the wall again. “I didn't know omegas could get pregnant outside of heats, or I would have worn a condom, Kacchan! It's not my fault I never learned all this! We thought I was beta...before...”
Katsuki's glare doesn't lessen, but his grip on Izuku's shirt does. “Fucking hell,” he mutters as some of the fight drains out of him, and he drops his forehead onto Izuku's shoulder. “Fine, it's not all your fault. Fucking sue me for liking when you come inside me, you damn asshole.”
Izuku bites the inside of his cheek to keep from smiling as he carefully places a gentle hand on Katsuki's head. “I like it too,” he murmurs quietly. “We never really talked about kids, but...”
“We're keeping it,” Katsuki replies firmly, and Izuku smiles because even when they argue, they still know each other so well. “If you take the number one hero spot while I'm on leave for this kid, I will make sure to snatch it the moment I come back. You won't even see me coming.”
“But I like to see Kacchan coming...” Izuku replies cheekily, and he can feel the exact moment the pun lands with Katsuki, because the tensing is unmistakable.
Izuku hardly has any time to duck away from Katsuki's rage. “That's what got us into this mess in first place!” Katsuki shouts as he chases after Izuku, who laughs and hopes this ends in make up sex, as most of their arguments do.