Love is a crazy sort of thing, he muses.
He's not quite sure how it became so blurred, but he remembers there being—at one point—a distinct line between friendship and this thing he is feeling now that involves a whole lot of stuttered heart beats, sweaty palms and pretending. The only way he can describe it is, it was like one day, the earth was turning at its usual axis and Remus' days proceeded as always, and the next, the planet had changed its tilt without informing him, so that it seemingly rotated around the boy in the next bed.
Maybe it had realized too that it wanted a little of the brightest star all for itself, Remus doesn't know.
All he knows is that the comings and goings of Sirius never escape his attention anymore; the moment Sirius enters the dorm, gets up to take a shower, pulls a book out of his bag, breathes, Remus is aware of it. He tries to keep his eyes on his book, but his senses are wandering, drinking in the scene through the sound of Sirius' quill scratching on parchment, or the smell of Sirius' shampoo drifting towards him as he repeatedly runs his fingers through slightly too-long hair.
Remus wonders, idly, as he turns a page and for all the world pretends as if he is studying Transfiguration and not the boy sitting across from him, if anyone else thinks it's strange the way love so often involves this mild, subconscious sort of stalking.