I used to work for an adult video store that had a video arcade. In each booth was a trashcan with an ashtray on top and a small tissue dispenser on the wall.
Guys would turn the ashtray over and cum in the tray. Over the course of a day, some of those trays were full of jizz.
Every once in a while, a guy would come out and speak to me and I'd smell that bleachy cum smell. I always knew what he had just done.
To each his own, but I never would have done that!