Scratch Someone’s Back: Origin and Meaning

To help someone out and assuming that they will help you out in future

When you have an itchy back, it can be very difficult to reach the area of your back which your arms aren’t flexible enough to scratch. But why would anyone want to scratch another person’s back? Well, if you do, one day they may return the favour. They may scratch your back when it’s really needed.

We can use this idiom metaphorically to mean any kind of favour that you do for someone in which you expect a favour back.

– I don’t mind doing the washing up this time – she’s scratched my back plenty of times.

– If you do the ironing I’ll do the vacuuming – you scratch my back and I’ll scratch yours.

– I can lend you some sugar for your cake, but what can you offer me in return? – You scratch my back and I’ll scratch yours.