[Sirius winces. He's not doing a very good job of celebrating a birthday right now.]

I'd back you up. If anyone said something, I'd give 'em a black eye.

[He forces a grin, but it falls quickly.]

The stuff you're looking forward to is the sort of stuff that makes it hard to do kid stuff when you're an adult. Can't go about having pirate parties then, eh? It's....some of it's a sacrifice. A lot of it is, actually.

[Sirius puts a hesitant hand on Dipper's shoulder.]

For what it's worth, you're ten times more mature than I ever was at your age.