Original artwork, not a still
All I ask is that you keep up with me. If you can't, then that strange sensation you'll be feeling in the seat of your pants will be my boot in your ass!
Behind the line
What it means
Our interpretation.
The speaker sets a blunt condition: stay at their pace. Failing that comes a crude, sarcastic warning, describing an odd sensation in the seat of the pants that turns out to be a boot. It is a barked ultimatum mixing menace with mocking humour.
Context reviewed