scratch back
do a favor/something nice for someone in the hope that they will do something for you
If you scratch the supervisor's back he will help you when you need help.

"You scratch my back and I'll scratch yours," the customer said when we talked about the new sales contract.

[TahlilGaran] English Idioms Dictionary ▲

scratch someone's back
do a favor/something nice for someone in the hope that they will do something for you
If you scratch the supervisor's back he will help you when you need help.

"You scratch my back and I'll scratch yours," the customer said when we talked about the new sales contract.

[TahlilGaran] English Idioms Dictionary ▲

scratch one's back
v. phr., informal To do something kind and helpful for someone or to flatter him in the hope that he will do something for you. Usually used in the expression "You scratch my back and I'll scratch yours."
Mary asked Jean to introduce her to her brother. Jean said, "You scratch my back and I'll scratch yours."

[TahlilGaran] English Idioms Dictionary ▲