The piss equivalent of cumming, but instead of semen, it's just piss. For those that enjoy giving Golden Showers. Someone in the act of performing a poom.
Jane: "I hope you drank plenty of water today"
John: "Don't worry, I'm about to.. Oh no, I'm pooming!" *proceeds to give Jane the Golden Shower she'd been waiting for all day*
The act of sneaking into someone else's room, dropping a payload in their toilet, not flushing, and then leaving a note signed 'Pooping Tom' on the toilet seat. Usually occurs in college residence halls.
"Dude, someone left a big, steaming pile of feces in my toilet with a note that said 'Courtesy of the Pooping Tom'!"