Sir William ---
Some of your advise is seriously bad and risks parts of your anatomy that are hard to replace --- and thinking that you are going to get a firm enough hold on an atacking dog's lower jaw to dislocate it is folly --- you will get bit, on the hand and it's dam hard to repair some hand injuries, same for punching them on the nose ---
As somone who has been hands on breaking up and handeling many an aggressive dog I can not advocate anyone untrained ( or trained folks as a first line of defense for that matter) get a hand or wrist anywhere near the muzzle of an aggressive dog if you can avoid it, kicking and striking weapons are a much better idea.
In addition as a general word of caution your own dog may well bite you as well --- they are under attack, have a huge adrenaline dump and are going to be mroe or less firing at will --- just a warining as I meet people everyday who state that their dow would never bite them or anyone, obviously for good, well trained dogs this is the case, however even these dogs under the right stress will resort to defending themselves.
Now to address the posters questions of what to do:
1. Pre-attack / you know it is comming --- first off don't lose situational awareness and don't use flexi-leads unless you are in a very safe area as these put your dog way out beyond your control and observation, plus when the chips are down they will break, and are hard to hold onto, so in other words don't use flexi leads. If threatened, I would reccomend putting your dog up out of the fight zone if possibe -- carrying is an option for some --- parked cars are another -- this will keep an attacker from getting close --- I would rather pay to repaint the hood or roof of a car than to sew up my dog, The second thing I chose to do is put myself between the threat and my dog -- in this way if it's a problem them I AM threatened as well deadly force is indicated if need be. Backing out of the situation and leaving his "turf" is probibly the best first option, however if you are dealin with an extreamly aggressive dog you may well not have this option as it may happen quickly or he may pursue you. Like I said if he is coming at you and between you are between him and your dog then you are threatened, use of a bite sticck as described below, or pepper spary may be the next step to prevent attack, after that neutralization if need be with your weapon may be an option you chose to utalize because you have run out of others --- obviously like all things it's situation dependant and presuming that you are carrying a good weapon, with good carry ammo and feel the shot is safe (i.e. you are not shooting wildly at a moving dog 100 yards off in a crowded park) then you would have a very defensable shot in most jurisdictions as YOU were also threatened and had exahusted other options of deterrance / defense.
Though I do not have the referances, there have been several instances of situations like this I have read about and they typically workout ok for the person who makes the shot, as the circumstances typically speak for themself, again like and self defens shooting if you come off as a yahoo who likes your bang stick more than common sense you are going to have a problem however in most reasonable situations --- even ones where a neighbor reterived a weapon from home to stop an attack things were fine from a legal perspective, though there are no guarantees.
2. The attack is on --- first don't panic and evaluate the situation, stupid as this may sound in some dog fights at the shelter I have stood by for a a few minuetes while we got people and equiptment becuse little harm was being done --- a very common thing for an aggressor to do is come up and growl, grab some flank or neck skin and hold on --- the attaceked dog may submit and try and roll or may hold their grond and stand still and growl, however this is a relative stand off between the two dogs --- there is little harm being done as there is little chance of vital anatomy being damaged -- the WRONG thing to do in this circumstance and I see it all the time is for one person to grab, usually the attacked dog and try and pull / wrench it away --- the attacker takes this as the fight being on and will offten escalate things and roll or take a full neck hold so in this situation, if possible get two people and a pry stick to break things up as you wrenching your dog away without a method to contain or controll the attacker is just going to stimulate his aggression and once his bite hold is broken he is going to want to take another so you must either be able to controll him or occupy that bite with something other than your or your dog's anatomy.
Obviously getting a second person is not always possible and some attacks are savage so then you have to do it yourself, the best single thing is a stout stick --- Animal Controll Officers carry ASP batons for this and they work great if permited in your area --- what works best is prying the attackers jaw off with the bite stick and then "working" him away by letting him bite the stick and hopefully back away from you as you threaten him with this, though you are at risk here and your dog will be darting in and out between you or trying to protect you so you can imagine how hard this is going to be by yourself, most maladjusted pet dogs can probibly be eventually driven off however the serious problem dog, the fighting dog or the mis-trained protection dog is most likely going to stay at it untill some other person is able to physically contain them or they are made physically incapable of attack --- yes there are instances where a dog has to be physically neutralized beause of it's agression --- if you have to, you have to, make shure you shot is safe, esp. if you are at short dastances relative to the attacker, you and your dog. .
BTW for the poster who mentioned prosecution for shooting a dog to put it down, if it was done an an apropriate manner he will liekly beat that wrap unless they want to nail him for discharging a firearm in a city limit or something as gunshot dispatch though unapealling is listed as conditionally acceptable method to euthanize an animal, i.e. The American Veternary Medical Association recognizes it as acceptable if other alternatives are not available, depending again on the circumstances this should be enough to get him in the clear unless circumstances make it appear to have been an act of cruelty and not euthanasia.
