A Term Used in South Park To Refer A Douchebag Harley Rider That Is Loud,obnoxious And A Stupid Asshole and they ruin everything to turn heads making noises to attract attentions
Anything that lets you sit (chair, couch, etc.) is called asstray after you get up from it. Because the seat becomes hot after you sit on it for a longperiod. It is a blend of ass and ashtray (ashtray is hot as people drop the ashes of cigarettes into an ashtray).
(In a bus...)
Young man: Come ma'am. You can have my seat.
Old lady: No, thanks. I do not want my bum to get roasted by the asstray.