Kori,

I have a male pup who will be 11 mos tomorrow and is intact. He behaves exactly like you describe your pup when he sees CERTAIN other dogs. He is NOT dog aggressive. But one time, my neighbor's loose 100+ lb intact male GSD came into my front yard while I had my puppy on leash for a potty break. I told the GSD to get lost in no uncertain terms. Now my puppy thinks that GSD is our enemy and he will go bonkers every time he sees it, even through a window. Same posture as you described in your dog. He also does this when he sees a big off leash dog running in the park behind our house.

So I do NOT think your dog is dog aggressive. I know my puppy isn't. I'm not sure exactly what he IS doing, though. It's possible that as they mature they decide it's time to get protective? Not sure. I highly doubt your mom's dog has anything to do with it, my puppy currently lives with 3 adult dogs and he's kept separate from them most of the time with crates and ex-pen. He would play with them if he could, but he's relentless and they don't want to play, so I separate them. He loves them.

Body language: straining forward against leash, hopping on front feet (stands on back legs sometimes while barking), ears forward, no teeth showing, tail curled up over his back (he has a ring tail), very stiff muscles, low barking, hackles up. If he is on his flexi lead (only when in my fenced yard) he will run as fast as he can toward the dog until I hit the brake).

Anyway I'd like to second what everyone said about NOT stopping to deal with the dog when you see another dog. Just keep going like nothing is wrong, change sides of the street if necessary but don't try and get him to sit and focus on you because that takes a HECK of a lot of distraction proofing before it will work. Correct for ears perking up, but do heels, sits and about turns, speed up (that works well), reward for attention and ignoring the other dog.

Not sure if a flat collar will give you enough correction for this. you need an "i'm not kidding tool" - so your e-collar might need to be used for this work (I'm not familiar with them).

I posted about this similar issue with another of my dogs, a 3-year-old neutered male who acts aggressively to my neighbor's dogs behind a fence or dogs in the park. He also fence fights and he is on leash 100% of the time because he can get out of my yard and I fear for the smaller dogs' safety. The above was the advice I got from the board, it was slow progress but is working, especially when the neighbor's dogs are not barking. (He hates being barked at). Now, as long as the other dog minds it's own business, he is fine on walks and in public. We have made alot of progress with the above method.

My pup is a work in progress but he is generally fine in crowded areas (took him to an agility trial over the weekend), it's just when there is a single dog so it's harder to work on.

Kori,
is there a specific toy that Kodee has a special interest in.
And by that i mean a toy that he totally focus' on like a ball or something like that?
If there is, take it with you on walks and use it to distract Kodee. Or to at least take his focus off the dog and off his normal reaction.
If you can get him to focus on you & the ball, mark that behaviour.
Tucker did the same thing you described when I would step in front of him, he would turn himself into a pretzel trying to look past me or around me to keep the dog in sight.
But when i brought out his little blue bouncy ball, all focus was off the dog and on me and the ball and i would mark that behaviour.
I never even had to give him the ball, just holding it where he could see it while we kept on walking kept his focus totally on me and off his focus on the other dog.
I do realize that some people may say that getting him to focus on the ball and not you is not the best result, but it sounds like you are having a hard time getting his focus off the dog. So I would think just getting him to re-focus on the ball for now, then having him focus on you and marking these behaviours may help out.

Wendy