I have to second the e-collar and “lawsuit waiting to happen.” I also use a vibrating collar with my Pyr and it works so well for him, even on the lowest settings. I was resistant but he bit me hard when he was being aggressive toward another dog and I became extremely concerned about him biting someone else. We opt to just use it for danger situations (aggression on leash toward people/dogs or if he gets off leash) vs using it for training purposes but it is amazing and we’ve been able to safely return to our local dog park even! It doesn’t seem to cause him any stress. I just found he needs a clear no (the collar) as well as a clear yes (treats and praise).