User blog comment:IamJakuhoRaikoben/Chapter 410: Memento Mori, Review./@comment-31.61.131.131-20141123123209/@comment-112.198.90.55-20141123133651

Its kinda like a modern (and not really known) translation of Quid Pro Quo (since its Latin) the full phrase is, "You scratch my back, I scratch yours".