bum sex

A blunt British slang term for anal sex. The word 'bum' (British English for buttocks) does the heavy lifting here, making this one of those transparently descriptive compounds that leaves nothing to the imagination. It's used casually in British vernacular — sometimes crudely, sometimes humorously — and appears across comedy, casual conversation, and tabloid journalism. It can be used without specific reference to the genders or orientations of those involved.