The ill-fated S&M threesome between Charlie, his wife Marcie, and his secretary Dani. Marcie finds the whole situation hilarious, and can barely keep herself from cracking up. She starts running off to get her camera. In the heat of the moment, she forgets the chain on her wrist, the other end of which is attached to a clamp on Charlie's nipple. Tragiliciously, she almost rips off the nipple, and the threesome ends in some hospital's emergency room, where they have to explain what happened.
(Note to lurkers: Yes, it really is that corny. But it's a lot funnier when seen, not read.)