personally, i dont mean to offend. but i think rolling a dog (be it any breed) on their back to instill "authority" is going to prevoke behavioral problems. i can only see this prevoking more agression almost as if you would be "challenging" them. my pupperz growls a lot, but its nothing nasty, she just growls to be vocal. her bark actually scares herself though so she doesnt like to do it lol. but she will growl for attention, when cuddling, etc. i think you need to evaluate what the growl meant, was your dog trying to just be vocal, or did it simply want to be left alone. i think everyone needs to understand, with a dog, be whatever size, sometimes, they DONT want you up in their face. let me put it this way: if you were laying down relaxing, and someone came and grabbed your face and put theirs in it, how would you feel? i think dogs need a personal space as much as people do, and it needs to be respected just as much. if my pup wants me to get all kissy kissy with her, she lets me know, if not... i leave her alone, and i dont force that. i hope this might help you understand and work out your problem!