Sirius grinned, laughing outright at the reference. He didn't know if Peter was suddenly all right with everything... Probably wasn't. But the joke helped. Made him think that it would at least be all right.
He leaned his head all the way back, looking at an upsidedown Wormtail. "You're a good man, Pete," he said, a bit quietly. "And if you just keep scratching right there, I'll do anything you want."