I had to have a conversation with a guy on my staff who everyone, including myself, suspected was masturbating in the bathroom. Noone ever 100% caught him in the act, but he'd be in the men's room (it opened up right into the main cube room) for long amounts of time. And if you walked in the door, there would be a split second hustle-bustle noise from the stall and then it would be totally silent. It was a very awkward conversation. He denied it, but it seemed to disappear after that.