Hmm... the spots I tend to tickle are usually on a person's body, but I shall play your game, frog-sage.
If I could choose, I'd say on a lonely beach house at the sunset, with the window placed in the west, so that the coming light illuminates my ticklee's bound form, makes her skin shine like fire under its fading light, and all into the night when the moon and the stars would illuminate our unity.