Planning and prep discussions help with setting up the scene and establishing boundaries. I always get to the location early to set up...things like the tickle box, cot, mummy wrap, prepping beds, chairs, etc. with restraints, and getting the tools (and sometimes the camera) set up and organized.
Then the couple shows and we chat a bit, usually over drinks. Eventually there's a deep breath and we settle the lee into her first set of restraints.
Some partners like to help with the process, some like to just watch, and others prefer to wander around, sometimes even leaving the room or building, I suspect to imagine (and overhear) what's happening to their ladies.
In some cases the ladies will tease their partners, even a little derisively, which I think is part of the cuckold vibe. Things like "not you, only him" if the guy tries to help, or "you could never make me laugh like this". Other times it's more of a fun friendly vibe...couples have their own unique ways of getting into the scene.
Intensity differs as well. Some couples only want light tickling and teasing, but I've been with others who want the lady wrecked and begging.
That's pretty much it off the top of my head. Couples scenes are always a lot of fun. It adds another interesting dimension to the whole experience.
-Q.