Ben Wa balls
Ben Wa was a small wizzened Chinese inventor who liked to freak people out. He invented many different devices, one of which was his famous 'wiggly balls on a bit of string' that was initially invented for kids. The balls would wiggle and move of their own accord and were intended to be kept in one's pocket, to give the impression that there was some sort of creature (possibly a stoat, weasel, ferret or kitten) trying valiently to get out.
However, with the invention of the gameboy, such non-interactive toys were soon all but redundant so Ben Wa sold his shop to Ron Jeremy. Ron began running a highly successful porn emporium from Ben Wa's shop. One day (whilst clearing out the crap from the shop), Ron came across a box entitled "Ben Wa Balls". He took the balls out and being endowed with a particularly perverted sort of mind, immediately saw the potential. The rest as they say, is history.