'Involuntary Muscle Contraction'

[Butch]

Professor Higgins at the University of Sydney was giving a lecture on 'Involuntary Muscle Contraction' to the first year medical students. This was not an exciting subject and the professor decided to lighten up the mood. He pointed to a young woman in the front row and asked, ‘Do you know what your ars-hole is doing while you're having an orgasm?'

 

She replied, ‘Probably down the pub with his mates.’