Tas and Anna
Tas was a little surprised when Anna grabbed his hand and started leading him to meet her roommate. He was actually excited about it. He liked Anna, so it stood to reason that he'd like everyone who she liked, which meant he and Stefan would no doubt be the very best of friends.
He allowed her to lead him through the throng of guests, since he didn't really know where he was going or what this Stefan looked like, drinking his beer as he walked.