From take back + -sies.
takesies-backsies pl (plural only)
- (childish) Synonym of backsie (“the act of taking back or going back on a statement, promise, or agreement”).
2017, Sarah Dessen, Once and for All, New York, NY: Viking, →ISBN, page 164:“If I win, I get to decide who you go out with next. And it can be anybody, you can't dispute or refuse, no takesies backsies.”
“Takesies backsies? What are you, twelve?” I said. “And what about if I win?”