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!"
po joelh Јануар 2, 2008
1 more definition
I was visited by a butt welder in the showers last evening.
po junior Септембар 8, 2003