They're back in familiar territory now - with a twist, yes, but still familiar, smiling and teasing. This isn't too different from what they'd had before - it's just the next step.

Wash smirks a bit at the challenge. "That depends on how you feel about being climbed like a tree." He shifts his grip, releasing the hug and lightly dragging his nails down Chief's back. It's part making a point and part sidling into territory he's pretty sure Chief isn't familiar with - either way, Chief's reaction should be fun to watch.