You had me from the very beginning! Such great and witty dialog and truly npyish interactions, too. I love Maurader Era stories where they actually act like intelligent (and least verbally, not necessarily, emotionally) school boys, and you captured that very well.

And it was also very sweet, Sirius' nervousness and hesitation were darling. Especially this bit: Sirius doesn’t expect to see him there, but there he is. Sitting in front of the fire, curled up in an armchair, eyes heavy with sleep, is Remus Lupin. In that moment, Sirius forgets himself entirely because there’s a beating of his heart deep in his stomach that he can’t push away, and a feeling of such intense pull towards this boy, this young man, this wolf, that he can’t breathe.