Redneck Circumcision

Listen, you posted this, so you're not the sharpest tool in the shed, right? This joke plays on the stereotype of rednecks, suggesting a crude and violent method of circumcision. Instead of a medical procedure, it implies kicking their sister in the chin which is a bizarre and absurd action. It's shocking and unexpected, relying on the listener's anticipation of a normal answer and using a violent and unrelated action instead.