Naked dancing and bathing in hotel rooms.
This is basically a movie about a couple who hook up in hotels and have sex. They cheat together on various friends and spouses.
In the first scene, he has sex with her up against the wall of the room. His bare buttocks are seen a number of times as he thrusts into her.
In a more moderate sex scene, the man and the woman have sex in a bed. Moderate thrusting, we see her breasts and rear. Later we see her bush and his rear. More breasts and bush in later sex scenes.
In a scene on a balcony, the male lead is completely nude and full frontal nudity is clearly visible, while the female lead's genitals are obscured.