“I don’t wanna be a chicken, I don’t wanna be a duck, so shake my butt”
My informant learned it from a couple girls in second grade who made fun of him and shook their butts at them. He said that it feels like it means an insult because you’re calling the other person a chicken/duck. He remembers being very offended.
This was a song that was sung from time to time among young kids.
This seems to be the start of young children learning about gender differences, and a way to cope with them. One could even argue that this was a way that girls started learning about their own sexuality since the butt is a fairly sexualized part on a female’s body. Perhaps this was just a way that kids could bond within their own gender.