Gayness, like vampirism, is spread through intimate contact. Therefore, if you approached the Bumming Bushes at the far end of the playing field you were, literally, asking for it.
Hidden in those bushes were anything from one to five naked men who would bum any boy who came too near. They would drag him into the bushes and bum him until he liked it and thereafter he, in turn, would bum others and so on...
A brave group of boys once stormed the bushes and found no naked men but they did find a few lolly sticks an empty can and some string. This was all the evidence needed to confirm that some victim had been tied up and bummed with such vigour that a refreshment break had been necessary.
As the legend grew bolder the naked men were given names. There was Ram Bottom - the leader, Captain Kinky, Big Billy Bendy Bollocks and two others who always wore masks but were thought to be Mr Ellis (Geography) and the old man who swept up in the market and who had been caught masturbating in a public convenience.