[.... still, a freak. And shut up, maybe he named it just so yelling "stop that, small red dragon thing!!" could stop, because it was seriously inconvenient.]
Mapping them out? For what, you're going to... build a castle there? Start cultivating a plant that will destroy the world? [Both he would not think out of Sebastian's reach at all. But it's obvious that as interested as Stiles is about the caves -- mapping them out seems a bit extensive.]
Alright, dude, whatever you say. [He shrugs and indicates that, yeah, sure, lead on.]