Protagonist gets nude in a room; breast and back exposed

Alice completely nude looks herself in a mirror. Her thick pubic hair obscures any genitalia.

Lots of people in an orgy but mostly heads and thrusting not that graphic

In Alice and David's first encounter, they walk into a room not expecting the other couple to be engaged in sex. They proclaim that they just want to watch. The man steps back holding his erect penis to protest them watching. This is clearly shown but the penis looks to be prosthetic.