I like the Inverted Y position best because the feet are spread apart and the arms are raised high above the head which leaves the ticklee very vulnerable.
having the lee sitting on the edge of the bed with a simple pair of velcro cuffs on ...I had her raise her arms and then I tucked my head under the cuffs with her arms extended over head with me sitting directly behind her...she was then unable to lower her arms at all....such a fun position to tickle her in! Sides, ribs, and underarms were prime targets Much laughter was heard after that!
Hmmm lol I wonder....