Need help in staying calm with aggression

I honestly think its a natural reaction to slap at something that pinches you. My son was a pincher when he was a baby and I probably slapped at him every time. I couldn't help it. He wasn't being mean and I wasn't being angry. Its just my reaction to being pinched. As for how to calm yourself. Count to 5. Don't wait until she is out of control and don't do it only once. If she is getting mouthy, count to 5 and then respond with a sentence. Count to 5 and then say your next sentence and keep doing it. It slows the pace of the argument down in addition to giving you time to collect yourself. The trick is to use the technique even when things are just an acceptable level of out of control.