Scratch Someone's Back

return a favor<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Hey, Bea. I need some help stacking these boxes. Would you please give me a hand?

OK. And I need some help tidying up the house. How about your helping me out after that?

OK. If you scratch my back, I’ll scratch yours.

I know you don’t like doing housework, but I’ll help you with the boxes if you promise to return the favor.