First of all, hi to everyone. Hopefully you're up to reading my problem.
I would like to give you a brief history of my dog. He was adopted at 4 months, and I was told that he was a stray. I have no idea if he was with a family at first and then a stray or anything like that. He is a lab/cur dog mix (I believe--but of course, that is always uncertain). He is the sweetest dog in the world, he has his puppy issues that I'm still working on (such as playful biting and grabbing and running with things he shouldn't be). He is 15 months, but still very much a puppy. Now, as far as the aggression issues:
I think he was alpha male in his pack as a stray (they found what we think is his brother in the same vicinity). As a result, my fiance has power struggles with him at times. Sometimes, he will show his teeth at me too, but today, he took it too far. My fiance was nice enough to let him roll around in the mud and he was going to give him a bath. But, Jack absolutely refused to budge off the bathroom floor and would not go in the tub. He has shown his teeth at me before when I try to move him or put him in the tub, and this is one of the only times he does this (I will address the other time later). Once he's in the tub, he's fine. But, he's a 75 pound dog, and I find it kind of difficult to pick him up. So, I usually avoid the issue, and throw a treat in the tub and he jumps in and stands there and waits for his bath to be over and he's a happy dog! So, today, my fiance tried to pick him up to put him in the tub, and apparently (I wasn't in the room at the time) Jack showed his teeth and actually bit my fiance! This is the first time he's actually bitten. I agree with my fiance in the sense that I shouldn't be ignoring his aggression, and I should address it, as it could get worse later on (which is why I'm posting this).
Now, the other time that he shows his teeth is if he is being disciplined for grabbing a sock and running around the house with it, or any other type of item that he knows he isn't supposed to have. I will go to pick him up, and he will just flop down on the ground, on his side, and it makes it absolutely impossible to pick him up, so I grab his collar and his whole body drag him (I have no other option at this point). I do not choke him or anything like that of course, I don't hurt him at all, but he is soooo stubborn!!!!!!! So, he'll show his teeth if I try to pick him up, which is why I've resorted to dragging (which only works half the time)
He is the kind of dog that will rip anything apart in less than 2 minutes and eat it. He not only tears it apart, but he swallows all the pieces to it, it doesn't matter if it's sharp, plastic, cloth, cotton, he doesn't care. SOOO, I have to be sooo vigilant and careful as to what toys I give him (he has bones and a rubber ball which he amazingly hasn't destroyed yet).
He used to not let us cut his nails (but he's great to brush his teeth--weird I know--he likes the taste of the toothpaste I guess). However, we developed a technique where we cover his eyes and my fiance just basically lays on top of him (not hurting him of course) and I trim his nails and he's fine. However, if he watches me do it, he really gets freaked out and tries to run away or he'll show his teeth, so we just cover his eyes.
So, I guess my question is, what do I do about the aggression he's displaying? I would never get rid of him, but I just want to address the issues before it's too late. He's such a sweet natured dog, just VERY stubborn!! I'm going to read up on the NILIF stuff right now and I'm sure that will help, but any additional input would be greatly appreciated!
I hope I didn't scare anyone off with my longwinded post