give (one) tit for tat
To retaliate against one. The phrase is most likely an alteration of the Dutch phrase "tip for tap," which means "blow for blow." A: "Shelly's mad at you?" B: "Yep, and she's giving me tit for tat by refusing to help me plan this event." I know your brother hit you, but you don't have to give him tit for tat—find a better solution than that.
give someone tit for tat
Fig. to give someone something equal to what was given you; to exchange a series of very similar things, one by one, with someone. They gave me the same kind of difficulty that I gave them. They gave me tit for tat. He punched me, so I punched him. Every time he hit me, I hit him. I just gave him tit for tat.