scratch (one's) back

scratch (one's) back

To provide one with a favor; to do something generous, helpful, or beneficial for someone. Usually implies that the favor is expected or hoped to be returned in the future. The president has been accused of scratching the oil industry's backs with a series of executive actions that put them in a position to make a lot more money. I've been scratching his back for years now—getting him a job, helping him move into his apartment, lending him money to buy furniture. The least he could do is help me clean out my house before I move. Just get me the information on the senator I need, and I'll make sure it's worth your while—you scratch my back and I'll scratch yours, OK?
See also: back, scratch

scratch someone's back

 
1. Lit. to scratch, usually with the fingers, the parts of someone's back that they cannot reach. Please scratch my back between my shoulder blades.
2. Fig. to do a favor for someone in return for a favor done for you. You scratch my back, and I'll scratch yours. We believe that the mayor has been scratching the treasurer's back.
See also: back, scratch

scratch someone's back

Do someone a favor in hopes that a favor will be returned. For example, I don't mind driving this time-she's scratched my back plenty of times. It also is put as you scratch my back and I'll scratch yours, as in If you do the laundry I'll do the cooking-you scratch my back and I'll scratch yours. This idiom was first recorded in 1704.
See also: back, scratch