Reminds me of a somewhat less physical but equally embarassing moment when I was at Junior School. An attractive young lady Student Teacher had been assigned our class for her Teaching Practice. During one lesson she turned her back on the class, stretched up to write somethng on the board, and inadvertently unleashed what can only be described as a 'knicker-ripper'.

Showing remakably quick thought, she spun round, pointed at a random boy in the front row and said sternly: "You! Stop that at once!"

To which the equally quick-minded pupil replied: "Yes Miss! Did you see which way it went?"