FFguy,
What's up dude. I am reaching out from New York City, How are you this fine evening?
(I remember reading about this a long long time ago, but I don't remember the source of the info).
I have my college degree in history. I remeber way back doing a paper on ancient military tactics (time of the crusades, middle ages like in the movie braveheart.)
To answer your question, it was used as torture, to get information and force confessions. There is speculation that the Romans did it, the Chinese definetly did it, and there is some evidence that the Russians may have done it, usually for minor crimes.
During the Renassaince, the English and French did it. Like locking people in wooden stocks and using turkey or falcon feathers, or soft bristled horse brushes to tickle the feet.
They would also use animals. They would lock the person in stocks or stretch them out tied to 4 posts. Then the interrigators would pour water or sweet wine across the feet (or stomach) and let an animal like a goat or sheep, or dog lick it of the persons body.
This was considered a sadistic form of torture because the person would laugh uncontrollably to the point that they could not take deep breaths..and soon would become light headed or pass out.
About a year ago, two very good friends of mine, who were in an overly playful mood, jumped me and tickled me for almost an hour..they were kind enough to give me a break here and there to catch my breath, but after it was over my ribs were hurting..so you can only imagine what happened to these people in ancient times who were on the receiving end of this torture.