Cosima's smile is a little crooked - she's not entirely sure what to make of that reaction, but it's not bad, at least, and she was casual about it for a reason.

(It's not as if she hadn't said something publicly over the crystals. It's not as if Delphine isn't back at Skyhold and she's going to have to deal with all that eventually. Maybe the unitard joke was just confusing with no context.)

"I think I'll take my chances staying here unless I know the place I'm going is home, all in all."