BTW, Piper was a pound puppy. I adopted him on the last day before he was euthanized as at the time, Albuquerque had a 14 day (IIRC) period of adoption before euthanization occurred. He was in a kennel with his brothers, sisters, and mother, so I presume he was either born in the shelter, or the entire family was dropped off together.
As a puppy, I let Piper do cute things that I didn't realize were domination things. Richard saw the way I was with him, and he even pointed it out to me before we went to 6Y9, but I disagreed (FWIW, Richard is pretty good with dogs).
Fast forward a year or so, and Piper got ahold of a hotdog wrapper when I was living with my parents. My dad reached under the table that Piper was lying under to grab the wrapper, and Piper snapped at him and caught him on the hand. I understood that it was my fault that he got the garbage in the first place by leaving it in a location he could get it from.
About 3 or 4 days later, Piper was chewing on a Mammoth Bone and I walked too closely. He snapped at me, and I decided I needed to take control. I reached down again and tried to take his Mammoth Bone away and he attacked me, biting my arm about 5 times before I alpha rolled him to regain control over the situation. In the fray, I was bit a bunch more times, and I had successfully beaten down my dog (the only time I've ever physically beat him in his entire life).
At that point, I decided it was time to take back Alpha from Piper. I controlled his eating, I controlled his toys and playtime. He earned everything he got from me. This is also the time I stopped letting him sleep in my bed. He became much better behaved and I thought the problem was fixed.
In the next year or two, I continued the good habits, and let a few slip (I let him sleep on the bed, but only at my feet). I started controlling who entered or left the room first (always me), but my roommate refused to help and said I was being too controlling of the dog.
When Brianna and I started dating, he did not respect her. He wouldn't listen to her, and he was constantly challenging her for pack position. He still listened to me, but never to her. She started controlling everything he did and I sat back and let it happen. She controlled when he ate, she controlled his toys, and she controlled when and how he could come and go from each room, but he never really caught on that she was boss. She successfully taught him some new tricks (roll over, for one, which I never could get him to do), but she usually had to tell him multiple times to do things I could get him to do with one command.
After we moved into our house together, my father and I were bringing in a new patio table, and Brianna was holding Piper back from interfering with us (because he wouldn't listen to her stay command). He snapped and bit her on the arm, but did not break the skin. At this point, I figured that I had failed him and was ready to put him up for adoption at the shelter, but Brianna convinced me not to (she said she was afraid I'd hold it against her, but I don't think I would have).
She stepped up her domination, using the same tactics I used to gain Alpha, but he still refused to submit.
We got Otto last weekend. Piper seemed to love him at first, playing and rolling around with him. There were some domination struggles, and Piper kept losing, which I thought was humorous. Then Otto tried to take a toy from Piper's mouth, and Piper snapped, biting Otto on the ear (puncturing through the ear). Otto learned not to fight with Piper, and Piper seemed to be respectful of Otto at this point.
Then today. Brianna let the two dogs out back to do their business, and Piper jumped the fence (how, I'm not sure, but he always finds a way). She found him sitting out front and called him to her. He would not come to her when she called him, but let her approach him. She grabbed him by the harness and walked him into the house. She told him to lie down, and he wouldn't listen to her. She put him in his room (I never really successfully crated Piper, but I was able to train him to go to a room on command), and tried to close the door. When she reached into his room to close the door, he latched onto her arm and started trying to attack her. She pushed him away with her other arm, and he bit her other arm twice. She finally kicked him away from her and slammed the door shut, placed Otto into his crate (we're crate training him), and immediately headed to the hospital. At this point, she thought he had broken her hand and punctured all the way through.
Luckily, he had only gouged out a large chunk of skin on her arm, and given her a few puncture wounds on her other hand, but no broken bones. Lots of bruises, and a broken spirit (she is still trying to convince me not to give him away), but she's ok.
Just typing that, I can see a lot of mistakes I made. We're not sure what we're going to do about Otto, but whatever it is, I want to decide while he's still a very young pup. Part of me wants to say "Lets do it right this time," but the other part says "You don't need to **** up another dog's life."
Thank you for listening. BTW, throw one more step in there - after we moved in together, Piper had to learn to deal with cats too (he never did learn, and right now, we keep her cats in the master bedroom, and he gets the house).
truely. 
