The other thing to add, is if you do physically punish or repremand the dog, it must be done fairly and immediately. Not even a few seconds after. This way the dog now exactly what it is being punished for..
If i need to punish an animal severly, i grab it as hard as i can on the scruff on the neck with the left hand and raise my right hand as if i were going to hit it, but i dont..i almost pick the dog off the floor. Not round the jowls, as this is seen as aggression by the dog, not assertion.
Now, all i have to do, is raise my hand, and say no in a certain voice. no grabbing.. I dont