A hot, meaty smelling liquid bowel movement, usually experienced the day after a lukewarm steak bake from Greggs.
"Bloody hell, Susan. I wish I hadn't had that dodgy meat pie on the way home from the petrol station last night. My arse has been streaming botty bovril almost non stop since 5 this morning. My legs are numb."
British slang for the anus, so called because during making a sexual time it acts as the socket for the plug which is a penis, or buttplug of course, or on rarer occasions - you do you though, I do not judge - gerbils in toilet roll tubes.