A certain quark in a women's personality that when "pressed" will turn her into a bitch for irational reasons.
For example, some women “really care about the environment”. That’s a Cunt Button. If you hit it, said girl will act like a total bitch because you left the faucet running for thirty seconds while you brushed your fucking teeth. Big deal. If saving Mother Earth is so important, why don’t you turn your car off at stop lights?