They'd been stuck in close quarters for what feels like a lifetime, between Remus's tiny flat and now 12 Grimmauld Place. Remus would have thought sharing a dormitory with the Marauders for seven years would have prepared him for this, would have made Sirius slipping back into his life easier, but he was wrong. If anything, the past makes it harder. They're slowly being suffocated by the ghosts of their former selves.
Another day means another row means another evening spent tiptoeing through the empty rooms, trying not to disturb the tense silence. He doesn't even know where in the house Sirius has hidden himself tonight, and he decides that he doesn't care. Remus jabs at the tired old radio he had found hidden in a closet and mutters darkly about moody bastards before settling in to take care of some correspondence that he knows Sirius will never get to.
He's not sure how long Sirius was watching him before he whispers- sadly, almost to himself- "They played this song at James and Lily's wedding."
Remus startles, spills tea on his parchment, swears. "I'm sorry, what?"
Sirius laughs at him- the old laugh, the one Remus hasn't heard since before… well, since before. He can feel the familiar grin tugging at his lips in response. Sirius comes closer, the soundless steps he takes a constant reminder that he's not the boy he used to be.
"I said." He rests his hands on Remus's shoulders, stopping his futile attempts at cleaning up the spill. "They played this." Sirius leans over him, brushes his lips against his ear. "At Prongs's wedding."
Remus leans back into him, a silent apology for not being able to change the past. "I remember," he says with a smile. "You made those sad eyes at me until I let you drag me onto the dance floor." He tilts his head further back to confirm that- of course- Sirius is pouting at him. Just as it always had, Sirius's sadface is enough to melt any ice Remus has left. "Oh, alright then," he murmurs, and lets Sirius drag him into the middle of the room.
They sway there for the rest of the song, and the next three as well, pushing away the ghosts that haunt them both the only way they know how to.