fuss buss
Let's break this word choice down: fuss is like being fussy like being ornery and agitated. A buss is short for bussy which is short for boypussy which is another word for butthole. So a fuss buss (or fussy bussy) is a bussy that is being very fussy. A butthole that is not agreeing with one's current life situation at any given time.
Oh, my god, my fuss buss is erupting inside of my bussy! Get me to the bathroom!