A friend of my wife who was aware that she would be attending the above dinner sent her this anecdote.

A doctor who belongs to a social group and is responsible for booking the lecturers. With one day to go to the next meeting the booked lecturer rings to apologetically cry off. The doctor starts ringing round to find a substitute but by the day of the lecture has not had any success. So, he decides he will give the talk. What subject? Inspired, he remembers his wife will not be attending, so he decides his subject will be 'Sex'. When she asks what he will talk about he hurriedly says 'Sailing'.
Some weeks later he and his wife are at a social function where a friend congratulates the doctor's wife on the wonderful lecture she had missed. Puzzled, the wife replies that she cannot imagine how as he hates the whole thing and has only done it twice.
''The first time he tried it he was thoroughly useless and the second time he threw up the whole time and swore he would never do it again!''