example 1  kid 1: 'why were you and mike in the toilet together?'  kid 2: 'dunno'  kid 1: 'err, bumwilly
a gratuitous term for [anal sex] often used by primary/early secondary school age kids descriptively or as a form of insult
"example 1  kid 1: 'why were you and mike in the toilet together?'  kid 2: 'dunno'  kid 1: 'err, bumwilly" What is the definition of "bumwilly"?