Man lifts up woman's dress up, they are kissing passionately, touching, then they lay down to continue. It is unclear if they had sex since the act was interrupted.
A man hears moans, he walks in on his wife having sex with another man, she's on top. You can see her right breast for a second from the side. In the same scene, you see other men in the bedroom. It is implied that his wife cheated on him with a number of other men in the room.
Dennis Quad has his shirt off in a number of scenes. In one scene, he is in a shower with only torso seen, when he steps out he has a towel on.