Their hands are so similar, in the dark he can't tell one from the other. Only at first, really, because then the differences are so glaringly obvious, a simpleton could pick them out.

The way Regulus' lips softly beg and then plunder, his hips rubbing against his trousers without even pretending to wait. The way he doesn't say 'love' when gasping out his name, but something else, a word with just as much emotion and affection behind it. When the beams of moonlight flitter from the window to the bed, their skins are so alike that instead of being two boys, two men, they're one pounding body of flesh.

Remus is different though, after a hesitation. His cool amber eyes and sandy hair aren't a perfect twin of his own colourings. His skin is harder, but so much warmer than any Black's. When his voice forms words during the middle of sex, a lick and tug on his ear, he breathes the words against skin. Remus knows the perfect way to play him, the exact movements which send every thought from his mind, every protest from his lips until he's compliant and ever so willing.

In the halls, when Regulus reaches out to ghost a hand over his lover's chest, a single motion from Remus and the battle's over before it ever begun. Remus can turn Sirius any way he wants, and he pulls him away from his brother, from his family, just as easily as leading him by the hand. When Regulus finally stops pursuing, and turns to another comfort, it always looks like the one he never touched.