pauloLaughing hysterically at the amount of soggy paper "peas" stuck to his back as he left the lesson an hour later totally unaware of the fun that had been had behind him. :) 

We had a biology teacher called Dr. Maggs who always had on the brightest white lab coat you could imagine. In the morning. By the end of the day, the back of it would be covered in ink splashes. At my school we were made to use fountain pens. As Dr. Maggs walked up and down the class delivering his fascinating biology lessons, we'd flick our fountain pens at him when he had his back turned. The poor guy never said anything about it and to this day I'm convinced he bought 5 shiny new lab coats at the end of every week.