A Professor of Medicine was lecturing on "Involuntary Muscular Contractions" to his first year medical students. Detecting boredom and realizing that this was not the most riveting subject, the Professor decided to lighten the mood.

Pointing to a young woman on the front row he asked, "Do you know what your ass hole is doing while you are having an orgasm?"

She replied, "Probably deer hunting with his buddies."