What is your asshole doing while you orgasm..

A professor was giving a lecture on uncontrollable muscle contractions to his medical students. Knowing that it was a boring subject he decided to spice up the lecture.

He pointed to a pretty blond women in the front row and asked, “do you know what your asshole is doing while you orgasm?”

She replied, “10 to 1 he is out drinking beer and fishing with his mates.”