Correct way of meeting
Do not approach stray dog, or more than one, if you do not know it or it shows that it is interested in meeting you. On the other hand, if you do not wish so because you are afraid or simply you do not want it to approach you – ignore it, without sudden moves or talking. Do not withdraw, just keep your space if you are standing or sitting, or your track if you are walking. This method of avoiding the meeting is applicable to owned dogs as well.
If you wish to meet the dog, there is only one proper way, although, in some cases, improper way can be pulled off without any consequences.
First and foremost, you should ask for owner's approval to approach the dog. Even if the dog does not show discomfort because of your presence, and will let you pet it, it is always for the best to start with meeting ritual. Get close to it, but not too much. Do not enter its space. Crouch down in order to be within dog's height (if you are the same height there is no need) and turn sideways. Do not look at its eyes or snout, look in front of yourself. Do not talk to it. Let it get you know you with smell first. That is why you should ignore it and be calm and steady and not showing fear while it sniffs your feet, shoulder, back... Do not make sudden moves with your arms, but keep them close to your body. When the dog gets all the information it wanted, it will either walk away or will get calm or start wagging its tail gently.
If the dog does not want you to approach it, it will distinctly let you know. Commonly, it will just turn and walk away. Do not follow it! Another way to let you know that it is not interested is very steady, steady almost stiff posture. It will avoid eye contact and will turn its head away to the other side, growling can be possible as a signal of warning to not approach it. Humans very often consider such dog as aggressive. That is not true. It just does not want you to approach it. It wants to avoid you. It may raise its tail, but it will not match ears which will be lowered, and its head that will be also slightly bent downwards – due to insecurity.
If the dog wants you to approach it, it would be the best not to show euphoria and excitement until it sniffs you. Then, offer your hand as a fist, fingers upwards, so it can smell it. With humans, a fist signifies fight, and open palm signifies greeting. With dogs it is different. If it is not showing signs of anxiety or aggression, but good mood, you can pet it. It is always wise to start petting unfamiliar dog from the back toward upper body, or on the side. With your arm down, pet its head or shoulder from the side first. Wait for the dog's answer. If the dog does not show disapproval and lowers its head and ears or gets closer to you, you can pet its back on the sides. If it turns ears backwards close to the head, growls or bristles – something does not suit it. Calmly end any further contact.
Wrong way of meeting
This is why, approaching unfamiliar dog with stretched arm to sniff it and gets to know us is a common mistake. In this context, reaching with hand, and skipping previous steps of correct meeting, a dog can identify as a challenge and possible attack, especially because it is usually accompanied by direct eye-contact. For a dog, direct touch is certainly not the first step when meeting someone.
Direct eye-contact and laughter are also mistakes. If you laugh, it can think that you are snarling at it, which is an invite to fight. Also, laughter is an expression for high level of energy, when dogs need calmness with introduction. This is why you should not run towards it or make any sudden moves. On the other hand, sneaking around the dog or touching it while it is asleep awakens its self-defence mechanisms and it might bite. It is most common with child-dog encounters. First time seeing a dog and immediately touching its belly, tail, ears or legs is dangerous, as well as approaching it when it is giving warnings – sharp barking and growling. Do not approach it then! You should not approach it so your head is placed above the dog. It is one of the signs of domination, so a dog can interpret it that way, like the first touch should not be on the top of its head or upper neck.
Even more wrong, more dangerous way of approaching a dog you do not know, is when it is holding something in its mouth, chewing or eating. It can trigger feeling of endangerment. The dog can read it as your attempt to seize that object.