“‘Tsumu,” his brother says quietly. Atsumu hears him let out a shaky breath and inhale slowly. They’re sitting on Atsumu’s bunk; the top one because Osamu didn’t want to fight for it when they bought it, three years ago.
“Hey, what is it?”
“I― I have to tell you something. It’s been bugging me for a really long time, but I need to get it out there, okay? Don’t be weird and stuff, please. I dunno how I could deal if you do.” Osamu looks down off the edge at the floor, away from Atsumu’s eyes.
“Yeah?” he prods. “You can tell me.” He pokes his brother, a sharp jab in the shoulder to comfort Osamu.
“Don’t poke me,” he protests.
“Then talk to me.” Atsumu pokes him again.
His brother opens his mouth, mutters something so quietly he doubts either of them can hear. A third poke, to his cheek this time, gets him to properly raise his voice.
“Atsumu, I― I’m not―”
“Not what?” He yells in his impatient twelve-year-old voice. “Spit it out, ya big baby.”
Osamu glares at him. “Stop interrupting me. It’s hard to say, okay?” Atsumu rolls his eyes, but listens anyway. “I’m not― not straight.”
Osamu buries his face in his hands. “See, you’re being weird about it. This was a mistake.” He gets up and tries to climb down the ladder, but Atsumu grabs his arm.
“What I meant to say is,” Atsumu says, “that’s it?”
His brother’s eyes widen. “What do you mean, that’s it?”
He tilts his head. “I thought it was gonna be something like, dunno, you were secretly a cryptid hunter or stuff? Don’t look at me like that, I don’t know!”
“A cryptid hunter? Really?” He looks relieved, though, that Atsumu isn’t freaked out or whatever.
“Hey, ‘Samu, don’t be bugged out!” He pauses, trying to think carefully about what to say next for once. “Well, I mean you can be bugged out about not being a cryptid hunter, that makes sense. But the straightness thing? That’s perfectly fine to me! In fact, I don’t really think I am either.” Atsumu stretches out his arms with a grin and envelopes his brother in a rare hug. “I mean, I like girls, but some boys are really cute too! So I’ll have your back if you have mine, okay?”
Osamu hugs him back hesitantly, as if he still can’t believe Atsumu isn’t bothered by his confession.
“Besides,” Atsumu rolls his eyes, “You’re in sixth year. Waaaaaaaay too little to have a boyfriend!”
“We’re the same age, ‘Tsumu,” his brother grumbles.
“… Oh yeah.”
“I can’t believe you sometimes.” Osamu untangles himself from the hug and climbs down the ladder. “Volleyball. You coming?”
“Can I be setter this time?”
“What do you mean, this time? You always play setter.”
“Because I’m better than you at it.”
Atsumu tackles his brother from behind before either of them even make it out of the room.
“Gerroff me!” Osamu yelps.
“No way,” Atsumu grins. “You’re stuck with me for life.”
“Suck it up, buttercup.”
“Don’t be rude!”
It’s quiet for a moment, before Osamu says something in a lower, serious tone. “Thanks, ‘Tsumu. For being okay with the gay stuff.”
“You’re welcome, ‘Samu.”
They get up again in comfortable silence and walk down the halls, Atsumu trailing his fingers against the walls out of habit. “You know, we’ll always be there for each other, right?”
"Even when I steal your pudding?"
“Shush. Even when we’re all old and wrinkly and married with lots of grandkids?”
Osamu scrunches up his nose. “That’s way too far in the future to be thinking about now.”
Atsumu pokes him.
“Yeah, yeah, we will.”
“Good. Now, where did you put the volleyball again?”