At your local dog park.

[ElleBelle]

If you have a big dog in a full body harness you're working way to hard. Those allow the dog to move freely except where you are able to bodily check him. It gives you no advantage.

I usually use what are commonly called a choke chain but of course I don't use them to choke the dogs. It simply gives me advantage. When I correct for surging ahead I just pop the leash, I don't actually strangle them. For really big and stubborn dogs they make a collar with teeth that dig into the dog. Those complete work but make you feel like a meany. The best one I've tried is called an English Training lead. It looks like this:

http://www.lambertvetsupply.com/product....fgodqBMACw

A loop goes around the neck and another around the muzzle .. but not in a way that prevents them from panting or drinking or biting for that matter. But you attach the leash to a ring just below the muzzle. That means the dogs head and nose is yours to lead where you will and he will follow. Gives you a tremendous physical advantage. My dogs hate theirs but are super easy on leash.

This is how I feel just thinking about trying to get my mongrel in a muzzle.