[Sirius runs a hand through his long hair, contemplating his next move.]

You win, for now. I won't come see you yet but you've gotta keep talking to me 'til Snape gets there, 'kay? I don't really care what you want to talk about, how much you hate me, how much mother probably still rants about me, what your favorite tea to drink in the morning is, doesn't really matter. Just pretend your me and don't shut up.

[But if something goes wrong while they're talking before Snape gets there (hell, even after Snape gets there) he's grabbing his bike and flying over there, not really caring about what Regulus wants or not.]