When a seated man farts, and the resulting air travels forward up your barse and builds up under your scrotum, creating a bubble, instead of exiting straight outyour arse.
A term used to demean someone so stupid and useless, their nuts have become bubbly and withered in an attempt to stop them from passing on their terrible genes
A Bumble Nut is other wise known as a small ball of faeces that has not been wiped properly and sticks to the hairs around your anus, and is left so long it has gone hard. The name derives from Bum-Ball-Nut but recent accents in recent times have thus changed this to Bumble Nut
In school we went swimming and my mate Benyon tried to change into his trunks but his underpants were caught on his Bumble Nuts.