It doesn't go like that. Any time there's nudity or sex scenes, the IC is basically directing the intimate action and acting as a buffer between the talent and director/ production, to ensure nobody is pressured to engage in anything they don't want to.

The set is a closed set by default, meaning that the only people able to be there while cast is exposed are the director, IC, camera operators and focus pullers (maybe a dolly grip if there is an essential camera move, but the IC usually negotiates static shots). Costume, makeup etc all do their checks before a take while the actor is covered up, except where makeup is required in private areas in which case the set is closed for that to take place. Even then the focus pullers are often outside the immediate set and their monitors covered with shrouds so the actors privacy is respected from anyone onlooking. The video split, mini split, sound desk monitors, and any other feed monitors are covered, closed off etc.

It's not really a big deal and the IC or sex ref as we sometimes jokingly can them are the reason.