Violent pinch off. This occurs when taking a shit and one's b-hole inexplicably contracts.
"Ben was growing a wonderful toilet tail until a VPO ruined it all!"
by ryry want wingy November 27, 2011
Acronym for "visible penis outline," as in, the outline of his penis is visible through his trousers.
"omg did you see that hot guy over there? VPO. and it's huge."
by Yoyo Lolo August 25, 2011