Not the requester, but I'm up at an ungodly hour and I think this fic is delightful! A lovely treat before slipping into bed myself. (Unfortunately not between two cute geeky friends, more's the pity.)

He glances in the mirror when he pulls his shirt off, huffs, and shakes his head. Taliesin likes himself well enough, but it’s not always easy to hang out with gorgeous skinny people all day. He can’t believe Los Angeles hasn’t beaten that out of him yet.
Oh gods, I feel that so much. This city is ridiculous. Everyone is hyper conscious of how they look and nobody eats dessert. Seriously, I was out to dinner with my co-workers and the waiter was SHOCKED when I asked for the dessert menu. "You're not from here, are you?" he asked. I mean, no, but how is that what clued you in?

There has always been this- tension when they’re at a convention, all three of them or either of the happy couple paired up with Taliesin. It’s like these weekends exist outside of the real world, where even they, in all their weird-ass glory, have to follow certain rules. It’s as though he could lean in a little closer when Matt slings a companionable arm around his shoulder, or when Marisha hugs him tight he could tilt her chin and just-
You really hit the nail on the head about cons being these like, liminal spaces, where societal rules kinda shift slightly and normal behavior changes in small and large ways.

Taliesin is about to drift off when two pairs of lips press against his face, and he feels arms wrap around his middle. It’s surprising but not so foreign that he jolts out of his half sleep. Instead, he finds himself smiling softly as Marisha whispers, “‘Night, babes.”
Yeah. This feels right.
Awwwwwww! Lovely ending to a lovely little ficlet.