Use this song as an opportunity for your students to choose to be the same or different!
If they want to be the same, they can simply echo your "song" (your improvised antecedent phrase). If they want to be different, they can create a consequent phrase to your antecedent.
Some example antecedent phrases appear below in the notation.
Inspiration: Thanks to Jennifer Bailey for the idea of giving kids the choice to be the same or different! Check out Jennifer's blog for lots of terrific ideas: https://singtokids.com/