People seem convinced that what causes tickling is the element of surprise. Thus, you can’t tickle yourself because you know what’s coming. But I don’t think effective tickling depends upon surprise, but trust.
And, though I am not able to back it up with any research, I firmly believe there are conditions under which you can successfully tickle yourself. But, it is dangerous, because what if you don’t stop…
And you tickle yourself until you die.
self-tickling machine
http://www.halfbakery.com/idea/self-tickling_20machine