In a car, a seat heater that roasts your ass to the point where you think your cheeks are going to melt together.
friend - "Holy crap, dude, my new car has seat warmers, and they're total butt-welders!"
ayon kay joelh ika-02 ng Enero, 2008
I was visited by a butt welder in the showers last evening.
ayon kay junior ika-08 ng Setyembre, 2003