Sexual act during which a female sits atop her partner (gender irrelevant, though originally adopted by partners of opposite sexes) who is on all fours, being ridden like a horse. The female stimulates her clitoris by gyrating upon the raised bumps of the spine.

the thing that you don’t have when you’re phones percentage is over 20

when Tickling someone who doesn't want to be tickled you take the Tickle back.
saying tickle-back! automatically takes the tickle away. like it never happened and the person who encountered the tickle will automatically forget they were being tickled.