Welcome to Gaia! ::

This game has a couple of different styles, which I'll outline, but first:

You need two willing participants and an impartial judge. (I suppose you can do it without the judge, as long as there's nothing at stake.) During the game, their tummies must have the same level of dress: either both must be bare, or both must be covered. (If one participant can't bare her belly without baring something she doesn't want bared, then either she has to change, or the other participant must leave the tummy covered.)

Version 1. The participants lie on their backs parallel to each other, but with heads in opposite directions, so that each tummy is within reach of the other's hand.

Version 2. The participants sit in chairs that are partly beside each other, but facing opposite directions, so that each participant can reach the other's tummy.

For the game, each participant starts with the near hand poised and ready to tickle. Then, possibly at some signal, they start tickling each other's tummies. The game ends when one participant:

a. tries to use the other hand to tickle, as well.
b. is so tickled that he can't keep tickling, and stops.
c. gets away from the other participant's tickling. (A participant might try to escape, but the game is still on as long as he doesn't succeed.)
d. tries to stop the other person from tickling through means other than tickling or escaping.

In any of these cases, the other participant wins. (Optionally, the winner may choose to tickle or be tickled by the loser.)

Variation: Instead of the entire tummy, the bellybutton can be the tickle target!