Keijo!!!!!!!! - On Your Mind -

From the introduction: A game of tactical butt-clashing. User summary: Keijo!!!!!!!! is a lightweight tabletop implementation of the Keijo!!!!!!!! / 競女!!!!!!!! manga series. The game centers around the fictional women-only sport of keijo, where players stand on floating platforms and aim to incapacitate or push opponents into the water, using only breasts and buttocks.