Farmageddon on 14 December 2010
I think superchunk's idea of just telling her the right way to do it is a great first step. If it's too late for that or she actually knows what she's doing, then go for explaining the idea (not the precise meaning) of the gesture and why it's a bad thing to do. If it too fails maybe get your parents to stabilish a swear-jar if she has an allowance and they'll cooperate. If you can't do that, then just tell her you'll break her favorite doll's neck if you find out she did that again, and make sure to come through if she does :P
