Hog-tied, with honors to . . .
Hog-tying a ticklee making it each to switch back and forth between her feet and sides. The drawback: no eye contact unless a mirror is in the right place.
And as eye contact adds a lot to the experience, coming in a strong second place is arms tied overhead, her legs either restrained to the floor (as in a dungeon, standing) or the foot of the bed (on her back). Then I can get close to her face as I tickle her midsection and underarms.
And coming in a strong third, with her back to me on the bed, provided she wears a thong, as I'm quite the ass man and like tickling a girl's bottom.