While having anal sex with a woman, asking her to tighten her sphincter muscles as you come.
Damn my dick is sore, I shouldn't have had that chick put the muffler clamp on last night.
When a women squeezes her legs tight around your head, as you are eating her out.
Eric: "I have a massive head-ache"
Dave: "how come?"
Eric: "I was eating this girl out, and she gave me a muffler clamp"