Same tech. Same idea. Just make sure to hook it up fused and with a rheostat to adjust the heat. May not need that much heat on the booty, thanks to the bodyfat and bloodflow difference as opposed to hands.
I'd just be worried about your weight on the circuit materials.
Try it. See what happens. I've put seat heaters in a lot of car seats that never came with them. Never done it on a bike.
So there I was walking into a biker bar in Chattanooga with liberty spikes on my head and a drag queen beside me... - bcurvin