(n) A rank collection of dust, formed by years of dead skin, dried farts, and dandruff that collects on office chairs or anyplace else people put their gross asses.
Philly was doing his 'Ace Ventura' bit when he slammed his face onto an office chair. You should have seen the gigantic cloud of ass dust that exploded out of it.
Your in a bathroom stall, but instead of shitting in the toilet you shit on the floor, ceiling, and walls, and end up puking in the toilet but missing.
Pretty much, you get your shit all over the fucking place. And not the fucking place it should be.