Post a number. If you're a guy, add 1 to the previous post. If you're a girl, subtract 1. First to either 100 or -100 wins. We start at 0. You cannot double post.
Example:
Guy - 1
Guy - 2
Guy - 3
Girl - 2
Girl - 1
Girl - 0
Girl - -1
Guy - 0
Guy - 1
Etc.
