• If the dogs are locked on to each other, hold them tight around the neck as still as possible to avoid more thrashing, if possible lift both dogs strait off the ground, the lack of traction will help keep them from thrashing each other more, often times you just have to sit there and hold them as still and tight as possible until the dogs let each other go.

Some people say, don't separate the dogs right away as they wont learn anything, some say you can physically choke a dog off of another dog, I don't have experience with that, but some people can do it safely. There are ways to help break up a fight more successfully if you have the right tools near you. A "break stick" is a tool designed by dog fighters to break up dog fights, but, this tool can be used by the average dog owner with bully breeds. Many people who obviously don't participate in dog fights own a couple of these including myself, used correctly it can be a very effective tool. A break stick is a plastic or wooden wedge with a dull point designed to be lodged in the side of the dogs mouth, near the back, you put it between the teeth when one dog has a hold on another, twist the break stick to pry the mouth open. This may not always work if the space is not there, but it can work, I have never used mine before.
I also have heard spraying water on the dogs will work, I've tried this, and it only stopped the fighting for a few seconds, and I think they just enjoyed the cool down, so for bullies, it might not take the edge off quiet enough.
Another friend told me about pouring ammonia and water on a towel and keeping it in a plastic bag to have near by, and that if a fight breaks out, to throw it over there head and they wont be able to see or breath very well and it can stop the fight.

Never EVER punch, kick, or hit a bull terrier in a fight, this WILL NOT WORK, I have seen mace designed for dogs FAIL in an attempt to stop a fight. Attempting to beat one dog off of another will just add fuel to the fire. I don't know how well human mace, tazers, or cattle prods will affect the out come of the fight.  I would be more afraid of doing more damage to the dogs than what they will do the fight itself. Doing things like this may just add more damage in the end.

Never assume your dog's will never get into a fight, even the best of friends, siblings, mating pairs can get into a fight. I always recommend never leaving dogs alone unsupervised, as I have seen this mistake leading to dead dogs. It only takes one mistake, even if there has never been a problem before, you don't want to NOT be there if that one time does occur.

An accidental fight story

I was at the dog park letting the dogs play in a pen by themselves since Scarlett and Bowzer were engaged in a game of tug of war, which they have done many times without problems. This day Scarlett was feeling more pushy and high strung than normal and as I noticed this I was preparing to break it up, as Scarlett's mouth got closer to Bowzer's on the rope, she slipped, and went in to get a different grip and grabbed a small piece of Bowzer's lip which led to an immediate fight. They were jumping all over each other and I started to reach in and realized I would have gotten bit, I waited until one dog grabbed the other by the face and I grabbed one collar, and than the other dogs collar and held them up on there hind legs. They let go of each other and I stood there holding them both by the collar and said "HEY!! Thats enough!!!" They were looking at each other and than they turned there heads away from each other, I let them go, and they walked away without further problems. This lasted a very short time and nothing more than a few scratches, but still no one wants to see the own dogs get into a fight. Fighting within my own pack is a very rare occurrence as I do everything I can to prevent fights, feeding in kennels, bones in kennels, and I always supervise them at all times. I learn what triggers each one of my dogs may have, and pay close attention to the possible warning signs.