Using her middle finger

Mackenzie (4): "Look, I know how to use my middle finger. It's easy. You just put in your thumb, pinky, pointer, and ring finger and hold your middle one up"

Meghan: "Who taught you how to use your middle finger?"

Mackenzie: "I taught myself, and, look, I just taught you"

Out of the mouth of babes...

So Meghan calls me and says, "At what point do I tell my child it is inappropriate to use your middle finger?"