Remus had long ago forgotten his shyness around Sirius. When he'd come to Hogwarts, it was as a lonely, secretive, and standoffish child. He had, in the past seven years, grown into a man, and that man had friends- friends who knew his secrets, friends whose touch he craved.
Though Remus had to admit he didn't crave any touch so much as he did Sirius's. Sirius was generous with his body, always willing to throw an arm around someone or lean on them. It was sort of another way in which Sirius was 'loud'.
And so when Remus set his head gently against Sirius's shoulder, it was purely a platonic gesture.
Well, maybe not purely.
"Ah," Sirius sighed, "Friend of mine, we have got it made."
Remus suspected that Sirius was referring to tomorrow's graduation and their plans for the coming year. But, as Sirius slung an arm around Remus's shoulder, Remus thought, 'Yes, that we do. My friend.'