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