I feel for ya. I used to babysit a five-year-old devil incarnate. You know what the worst part was? His mother was a schoolteacher with a degree in child psychology.
Back in the day, kids got the razor strap for misbehaving. If they were brats at school, the teacher took them out back and whipped them with a willow switch, and they got it again at home when their dads found out about it.