Historically, stocks were used mostly as a form of public humiliation for crimes, starting around the time of the Dark Ages. Steal a loaf of bread, get caught, get declared a thief, and get trapped in a set of wooden stocks for some time where everyone can point and laugh and sometimes throw things and even hurt you. Tickle torture may have been used during those situations, too, but I think people would have opted to lobbing bad harvest at people, instead. Not to be confused for the wooden "pillory," which is a form of standing "stocks" for the wrists and head.
Nowadays, stocks are favored in the BDSM scene, and of course by us tickle fanatics. 😛 Many are still made of wood, but others can be metal. For the full experience, you should find a set and try it out yourself, Amber. 😉
