Luckily for Miles it was Sirius, and there was really no need for awkward introductions or introductions at all. Sirius was, in general, something of a social flower and since this week had been putting his emotions on notice, he was amping it all up a bit just to even it out.
He tended to take over rooms with his personality when he was in them. "Oi! Hey!" He grinned, all dimples and white teeth. "Miles, yeah? This is going to be an absolutely brilliant adventure. Space!" He made an exhaling noise that properly explained how exciting a concept that was. "What a way to get out of a comfort zone, huh?"
He was ready for it though. If ready meant a leather jacket and a pair of Doc Martens that were genuinely vintage because he'd bought them at a muggle shop in 1976. And his wand of course. But he never left home without that.