piss balloon

What uncut men can do if they wake up with a piss boner and pinch the end of their foreskin closed when pissing. The foreskin expands and becomes a piss balloon.

Best done in the shower, or over someone you either really hate or who finds watersports fun, as releasing the skin causes a real explosion of piss.

A balloon which someone (most likely to be male, and by chance happens to have a pack of party balloons at the time) may piss into at a festival or camping trip, like a waterbomb, if too drunk/tired/cold to leave the tent.
Just be careful not to pop it!