How do I stop my neighbor from touching my dog?

This particular neighbor thinks he can keep putting his hands on my dog, every time she is outside going number1 or even number2. He needs to keep his filthy diseased hands off my pooch or else one if these days I will take a machete and frekin cut his hands off. Who does he even think he is watching my dog go to the bathroom anyway, it makes her get nervous, then she can't go number2. What should I do?