backsie

noun[in the plural]5

1. •
   The act of taking back or going back on a statement, promise, or agreement.

   • No backsie no matter what. — 1986
2. •
   The back.

   • A mimsy, a clapsy, I roll my hands, touch backsie, My right hand, my left hand, High as the sky, low as the sea, I touch my knee, and my heel, and my toe, And over we go. — 1985
3. •
   A reciprocal action or consequence, such as immediately tagging the player who has tagged one in a game of tag.
4. •
   The act of joining a queue behind a friend rather than at the end of the queue.

   • To her, the ethical thicket consists of "frontsies and backsies," a phenomenon she noticed in kindergarten. — 1988
5. •
   The act of going through a sequence of moves in reverse.

   • And then you play Backsies again if you're playing that way. — 1956