Scratch my back – I've got an itch.

给我挠挠背–我痒痒。

《柯林斯英汉双解大词典》

Can anybody scratch my back for me?

有人来替我搔背吗？

youdao

Scratch my back and I'll scratch yours.

你给我捶背，我替你搔痒。

youdao

She praises my work. She might even say "I will scratch your back if you will scratch mine."

VOA: special.2010.01.24

Normally, biologists explain this as being either nepotism or you-scratch-my-back-and-I'll-scratch-yours.

ECONOMIST: Human evolution: Moral thinking | The

As I tuck my pen into the place between the top two buttons on my shirt, I scratch my chin and the back of my head although neither itches.

FORBES: Lemon Squares and the Acceptance Thereof

"I was bending over to scratch her back with my hand, " she wrote under the photo.

NPR: Lion Killed Woman As She Was Cleaning Enclosure