Preshart

A common slang word used in South East England.

Portmanteau of "pre-shitty-farts" , used to describe the farts usually associated with a shit held in for a long period of time, where it is not clear if you have farted or actually shat yourself. also can be called a Russian roulette fart.

"we need to find a toilet, i've got some serious Presharts"
"that was a dirty Preshart I heard over there"