He feels an open summons and lets it grab him -
"We have more kinds of demons than we can count," says Rayne. "More than a few kinds of magic, for that matter. And gods, do you have gods? Gods are a nuisance."
"That's what I said, yes. And humans can do little tidbits of magic aside from summoning us - the catchall term is daeva - but most of the heavy lifting is summonses."
"See, you're not too drunk to explain it after all," says Rayne.
"Want to learn some magic?" says Rayne.
"Don't teach magic to the demon," says Ripper.
"But Ripper, you always help me with my bad ideas," says Rayne, batting his eyelashes.
"Well, I know you're not one of our kinds of demon, probably, but I don't know what kind of demon you are, and most of the kinds of demon I know about are bad enough with the magic they can already do."
"I can make arbitrary nonmagical matter. If wanted to suck the entire planet into a black hole, it would already be done. My knowhow is not the limiting factor on how bad I can get, but it might be the limiting factor on how much useful stuff I can accomplish while I'm here."
"Right, but do you really want to learn magic from two drunk guys who are careless enough to let you convince them to teach you magic while they're still drunk? How do I even know you're telling the truth about the black holes? I don't know a damn thing about your magic."
"I didn't say how about you start giving me lessons right now, I was wondering why it was such an obvious bad idea. I'm not going to even entertain the idea of me demo-ing the black hole on a planet's surface but if you want something else made I'll consider it."
"Arbitrary nonmagical matter includes, like, the ability to patch your ozone layer, I can't remember if that's known to be a problem yet? It's a problem later. My Earth, anyway. There's things I can't do, though, even with my sci-fi gadgets from the time travel part, so maybe magic could make me more well-rounded as an ozone-layer-patcher-errant."
"...I can't even think about this right now," says Ripper. "If you want to prove you can make things, you could make me another guitar."
And lo, there is a fancy futuristic electric guitar, very sleekly built. Cam hands it over.
"It's got its own amp in it, so don't turn that dial on the end too far unless you want to deafen the entire block."
"Do you two need to get a room?" says Rayne.