Good clean joke

A professor at the Medical University of South Carolina in Charleston,
SC was giving a lecture on 'Involuntary Muscular Contractions' to his
first year medical students. Realizing this was not the most riveting
subject, the professor decided to lighten the mood slightly. He pointed
to a young woman in the front row and said,

'Do you know what your ass hole is doing while you're having an orgasm?'

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

It took 45 minutes to restore order in the classroom.........