The Hokey Pokey is a song and a dance that first become popular in the U.S. in the 1950’s as a novelty (for fun; not serious) dance for adults. Since then, it’s become a song and dance that children are taught at home or at school for fun.
There are many versions of this song and dance. You can use or add almost any body part. The most popular body parts to use are foot/leg, hand/arm, elbow (the part of your arm that joins the bottom and top of your arm together), hip (the part of your body between your legs and your waist), head, and whole self (entire person).
You can hear the song here. (That version uses backside, a polite and and old-fashioned term for the part of your body that you sit on.) Or, you can watch a group of children sing and dance it with their teachers below or here.