Evan coming into Mike's room while he's out hanging out with friends to curl up in his bed with his pillow to his chest, breathing in his scent until his throat starts to ache and his eyes start to blur because he misses his big brother so much when he obviously cared about him. But now he's so mean all the time, and he probably hates Evan. And Evan kind of hates Mike too, because of how mean he is, but he still misses him.
He sniffles and cries quietly to sleep. He wakes up near sunset, when the front door closes, and he has to shoot up and hurriedly dart back to his room before Mike finds out he was taking up space in his bed.
But Mike already knows about it. Has known, for a while. Evan's careful most of the time about making it look like he was never there, but sometimes, he has to rush out of his room, and the imprint of his body is still in his blankets. And even without it, there's no way Mike wouldn't know— Evan's scent is pretty distinctive to him too.
Evan doesn't know any of this. And Mike never wants him to. Because he is kind of conflicted, every time, caught between annoyance and confusion and lingering longing. But also, because every night that Evan had sneaked a nap in his bed hours before, Mike can get off so much easier. An arm thrown over his eyes, door shut, keeping quiet while he rakes in breaths and works his hand over his cock. Sleeping comes naturally, then, perfectly. He wakes up more refreshed than when he ends up staying up all night staring at the ceiling.
It's a win-win. Of course neither of them will say anything.