About 2 months ago, my girlfriend and I adopted a 2yr old neutered male GSD. He is an intelligent dog and knows several commands which he cooperatively obeys (barring when he is overly excited/distracted... but I attribute this to his age) including your basic sit, lie down, come, and a couple of "cute" ones like sit up, give-me-five, etc. He is very protective... which I like... unfortunately, he doesn't seem to know when to stop. I like him barking at strangers, but once we have established them as friends and accepted them into our home I would like the aggressive behavior to end... and it does... temporarily.... only to start again seemingly without provocation. Once he starts, it's like death wobble, you have to stop, pull over and start out all over again... a simple NO will not suffice, the entire introduction process must be performed again. My girlfriend and I are also frequently the recipients of the growling, barking, and snapping. Keep in mind he is my [and her] best friend 98% of the time, obeys my commands, accepts handling, allows me to place his food in front of him and remove it at will. It usually occurs of a morning, when I/ Elizabeth are getting ready for work/ class. Once one of us leaves the bedroom to do the 3 S's, Logan will not [without a confrontation] allow us to reenter the room, come near the other, or the bed. I am affraid that he is going to hurt somebody. Not myself, I have been trained on how to handle/restrain combative dogs from working in the veterinary field, but he genuinely frightens my girlfriend, and I am affraid he could hurt her (he is pushing 100 lbs). I have tried "dominating" him (Forceably flipping him onto his back and holding him upside down and helpless until he ceases to resist for 30 seconds or more), to no lasting (or sometimes any) effect. Once released he returns to the same behavior. Whipping him when he is in this "mode" is actually counter-productive as the aggression only escalates. I genuinely love this dog, but I fear he will hurt my girlfriend, a guest, or worse escape the fence (he is a pretty good escape artist), hurt somebody, and get us sued. I have another GSD (Riley...intact 3yr old male) that we raised from a pup that would never think about showing a tooth to me or any of my friends. Logan was originally adopted to be his playmate following my recent move from an apartment to my first house. I don't have any money to dump into any professional training. Would continued at home training fix this? Anybody have any tricks? I thought it would get better with time as he became adjusted to his new home/ parents... unfortunately it has not changed. I called his previous owners to see if they wanted first dibs as I am strongly considering finding him a new home. He was originally a 75% outside/ 25% inside farm dog on 10-15 acres. He now spends 75% of his time inside and has a .5 acre fenced back yard. I think he would adjust better to another farm. My mom came to visit for a couple of days to see the new house, he snapped at her this morning, that may have been the last straw. Thoughts? Sorry for the long post.