It had started out with, as usual, an insult. Dean had called Seamus a leprechaun, and Seamus had pointed out that if you were an overgrown troll everyone seemed small to you, it was all perspective really, and then Dean had swatted Seamus on the back of his head and things had quickly devolved from there.
Which is why Dean is now sitting on top of Seamus, grinning widely and looking incredibly proud of his victory.
"You're about a foot taller than me, mate," Seamus says, laughing (difficult though that is with a sixteen-year old boy on his chest). "Don't see why you're so surprised every time."
Dean shrugs. "Leprechauns, you know. It's hard to pin them down, the sneaky little buggers."
"Oi!"
Seamus tries to think of a retort, but his brain and fine-motor skills appear to no longer be functioning. Dean is smiling at him, and Seamus suddenly realizes just how close they are. He would need to lift his head just the slightest bit, and they would be kissing, and then- well. And then Dean would shove him away in disgust, and their friendship would be irreparably ruined for ever and ever, all because Seamus couldn't keep his hands to himself.
Seamus suddenly feels queasy. "I've got to go," he says, trying to prop himself up on his elbows and muttering "thanks" as Dean moves off of him.
"You alright?" Dean asks, and Seamus nods and tries not to throw up. If Dean knew, he- well, he certainly wouldn't hate him; Seamus knows his best friend well enough to know that. But there'd be none of this easy comfort, none of the small touches and wrestling matches. There'd be a barrier here, and Seamus doesn't think he could take that.
Seamus can imagine the scene, has imaged the scene again and again, and he doesn't want to be sick all over Dean so he nods and gets up and leaves.
He goes to the Quidditch pitch, because even if he's not on the team he still loves to fly, and in the air there's no worrying about stupid, unrequited crushes on your best mate or the ever-approaching war. There's only the wind in your ears and the weak March sunlight on your face, and if you fall and get hurt it's the kind of wounds that can be mended with a spell, a potion, and a day in bed.