Peesome
When 3 or more people float next to each other in an ocean or lake, and all pee simultaneously. Likely the result of alcohol consumption.
"After spending the afternoon drinking beers on a boat, Heather, Jessica and I had a peesome while floating in the lake."
peesome
Combination of to pee and threesome when at least two persons (mainly male and drunken) pee in one loo sink.
Susan at the pub: Hey guys I am next and there is only one toilette working, can you please hurry and peesome?