The kind of tickling only a truly mature and expert tickler can think of doing. I am sure you would end up leaving the ticklee's tummy aching with laughter haha
It has to be my feet, especially the spots under the toes, the centers of my soles, the stems of my toes and in between them. Close is underarms and belly, waist, and sides.
Has to be my feet. Anywhere on the feet can turn me into a giggle-ball, be it the arches, insteps, right at the centers, the balls of the feet, the toes (the stems and between them). The ticklish sensation feels different in each of those areas but it tickles like hell for sure. Maybe the heels...
I think (at least with me that is the case) if something is inserted to tickle between the toes, then it is impossible to not curl them tightly because between the toes is a very ticklish area. And then you are right, if you want them to open up, you would need to tickle elsewhere to weaken the...