While Fenris doesn't precisely feel the need as Astarion does, it seems like a shame not to bite him back. A hungry creature, one hand finds Astarion's hip-- thigh, arse-- while the other works between them, keeping them in place.

Between gasps and rough kisses, Fenris pants, "they call this luctatio," in Tevinter, obviously. "Wrestling."

Honestly, he just thinks Astarion will find that funny.