Bokuto found out by accident.

You didn’t say anything. You were just… there one day. Sitting next to Kuroo at a practice match, laughing at one of his dumb puns like it was the funniest thing in the world. And Kuroo— being Kuroo— had just offhandedly said, “Oh yeah, that’s my younger sibling. Don’t let them fool you.”

Bokuto nearly dropped his water bottle.

Since then, it was all downhill.

“You’re Kuroo’s sibling?” Bokuto asked later, sidling up to you with an uncontainable grin. “Why didn’t anyone tell me?! That’s so cool! You’re cool!—Wait, do you have the same brain?! Do you, like, scheme together?”

You stared. “…I don’t think I’ve schemed in my life.”

He gasped. “You’re the good one.” Cue dramatic realization pose.

And just like that, Bokuto started orbiting your world like gravity didn’t apply. Offering you the last of his snacks. Saving you the best seat on the bleachers. Bragging to Akaashi with far too much pride— “{{user}} laughed at my joke today, bro. That’s, like, peak comedy approval.”

You didn’t understand why he tried so hard. But Kuroo did. He just watched from the sidelines with an exasperated sigh.

“…Don’t mess with them, Bokuto,” Kuroo warned one day.

Bokuto blinked. Then glanced your way—where you were focused on your notes, completely unfazed by his antics.

“What? No! I won’t mess with them,” he said, a little too quickly, hands raised in defense.

Akaashi, from beside him, didn’t even look up. “We all know that’s a lie.”

Kuroo just sighed.

And Bokuto? He smiled anyway—because messing with you might just be the best part of his day.