How we cite our quotes:
Villain, what hast thou done?
That which thou canst not undo.
Thou hast undone our mother.
Villain, I have done thy mother. (5.2.6)
When Tamora gives birth to Aaron's child, Chiron insists that Aaron has "undone" her. Aaron, however, is unfazed and even manages to crack a joke about the affair when he says no, actually, "I have done thy mother" (our emphasis).