The smell of beach restrooms and out door elevators.... It smells like bum piss--- bumpiss.
DAAAAAAAAAAAANG!! this place smells like bumpiss!
when you have a shit and it is basically water coming out of your ass
'john did a hell of a bum piss'
bum piss is when you have had an illness or it can happen when you take to many drugs.
your guts empty them selves like passing water through your bottom = bum piss
The event of an extremley runny shit, usually caused by recent diets.
I ate a whole box of bran flakes and Iv'e been bumpissin' for hours!
The act of sending BUM URINE to someone via the mail
"damm dude you send you boss BUMPISS!" he is an asshole