The Doctor heard the knock from his makeshift 'lab', where he was working on his little devices here and there. Upon hearing it, he looked around and up from his project, goggles worn on his face as he spun around and grabbed a nearby rope, tugging on it, which caused a lot of little gizmos and things to begin working in unison, until the door opened for Buffy, with no one standing there of course. Which was always a bit on the 'creepy' side, but soon the Doctor was stepping out from his lab, goggles still on as well as a fez.
Straightening his bowtie as he moved forward, dressed in white shirt, suspenders, and black slacks he seemed relatively normal if not a bit on the eccentric side. Big smile spread over his face as he moved towards her, "You must be Buffy! Brilliant to meet you, I'm the Doctor, I'd shake your hand but it's got goop on it. Strange bit of goop, really great for sticking things together, kind of burns though, but it causes a tingling. Brilliant feeling, tingling. You'd love it really. Never trust a person who doesn't like tingling, that's what I always say."
Instead he moved towards her and provided air kisses to each cheek then moved away, "Willow! Your friend is here to... whatever it is you do. Do you still play?" He glanced to Buffy, "Like pirates and Indians or what have you?"