What is the meaning of Mashed_potato?

Potato that has been boiled and mashed to a pulpy consistency.

A dance/dance move popular in Western culture the 1960s. It begins by stepping backward with one foot with that heel tilted inward. The foot is positioned slightly behind the other (stationary) foot. With the weight on the ball of the starting foot, the heel is then swivelled outward. The same process is repeated with the other foot.

Source: wiktionary.org