John W. achieved school-wide fame in the sixth form when he was spotted through a badly-curtained bathroom window having an energetic wank. Of course, indiscreet masturbation is hardly that unusual at boarding school, but two factors elevated John's performance to the status of School Legend:

1. In an impressive display of coordination and efficiency, he was brushing his teeth with his other hand.

2. He frequently paused in his manipulations to slap his cock energetically against the basin.

John was dubbed Basin Basher for the remainder of his school career, and "Arm & Hammer" toothpaste suddenly became hilarious. The event was immortalised in the following song (to the tune, vaguely, of Do your balls hang low?):

Is your name John or Jason,
Do you bash it on a basin,
Do you cover it in Colgate for better lubrication?
Does it give you satisfaction,
Does it get a big reaction,
Do you use Double Action for better foreskin traction?

The beauty of the final line is that John was a quiet, earnest student: the image of him diligently evaluating toothpastes until he found the one with optimum sensual enhancement was entirely plausible.