A lot of it depends on the particular situation and/or circumstances.
As a general rule, my GF prefers that I am naked, watching, and has no problem if I offer some occasional encouragement, compliments, and other hot talk. She wants to see my hard-on and watch me jack it while she is getting fucked.
We had a common friend she used to fuck; he was always very domineering, and 'manhandled' her. Nothing too rough, but he would definitely let her know who was in charge, and she was very submissive. She always wanted to put me in a cage while I watched them, knowing my dick would be straining to get hard but couldn't because of the cage.