[ which makes her laugh and pull her hand away again, leaning in to kiss his cheek before she settles back again ]

So it's decided, neither of us will go home. Which means Sirius will have to stay too, of course. I have a few more friends I'd like to keep here, but you, sir, you have to promise.

[ pinky promise! seeing as she's holding her pinky up between them now ]

Promise you'll stay here with me.

[ she knows he can't control it, none of them can. but even wanting him to make that promise means something, doesn't it? she thinks it does. so, she's doing it. ]