While sex acts are discussed heavily throughout the movie, very little is actually shown onscreen. The sex scenes that are present do not feature any nudity and are usually very brief.
Two men have sex: one man thrusts vigorously while the other man is on his hands and knees; the man thrusting announces that he is going to climax and does so. Nudity shows only bare chests. Very graphic scene.
A husband and his wife have sex in bed (they are both clothed in pajamas): we see the man thrusting vigorously on top of the woman, they stop and talk for a moment and then start again when he says "Let me finish."
A man pulls another man's pants open (nothing is shown) and moves down and off-screen (it is implied that the man is performing oral sex on the other man) and the other man says, "Don't bite."
We hear moaning on a boat, a man stands up and spits over the side of the boat and another man pulls his pants up from his ankles (we see his bare legs).
A man masturbates while watching a movie in a room with other men (we see his arm moving rhythmically).
A brief shower room scene shows nude men from the back showing full rear nudity.
Two men wearing bikini dance outfits dance in a club where other men watch and dance together. The scene is only a couple seconds long. There is no nudity.
A husband and his wife kiss passionately in front of several other people. Two men dance and kiss tenderly in an extended scene.