The film I am looking for is a retro where there is a scene of a female fashion or ad photographer taking pictures during a photoshoot. The male model accidentally gets a boner and thus makes the photoshoot impossible to continue. His model partner tries to help him by giving a BJ, but the boner does not go away. The female model makes a sacrifice and lets him fuck her. They go at it in different positions while the female photographer keeps checking her watch. Obviously the scene comes to a blasting conclusion by the male model.

Later at home the female photographer is talking to her man on the phone, and she decides to go over to his place and they go at it too. They keep taking polaroids while they are doing it.