In the start of movie we see two couples having sex but no nudity is shown

in a scene a man forces a girl to strip but no nudity is shown

In a scene a man forces a women they have sex man thrusts from behind only mans butt is shown and then we see both of them laying on bed so its not a rape

There is a proper sex scene where the girl think falshback so male and females buttocks are shown while we can see girls breast