"Can I pet your dog?"

Most of us want to say yes. A good neighbor lets children pet his dog, right?

"People want to be nice," says Colleen Pelar, dog trainer and author of "Living with Kids and Dogs... Without Losing Your Mind." "But by being nice to people we're sometimes not nice to our dogs."

Many people don't recognize the subtle signs of stress in dog body language. You may not realize that your dog tolerates being petted by strangers but does not enjoy it.

"If we don't see that, we're going to be blindsided on the day that's more stressful, when four kids come over and your dog snaps," says Pelar.

There's certainly no need to panic about the odds of a dog bite. In her book "Dogs Bite But Balloons and Slippers are More Dangerous," trainer Janis Bradley gives statistics showing that more emergency room visits can be attributed to accidents with furniture or footwear than interactions with dogs.

But no matter how small the chance is — no matter if it's just a snap and not even a scratch — you know how bad you'd feel if it was your dog. So follow a few simple rules, and understand some basic elements of canine body language.

• Most kids know to ask the owner if it's OK. But, Pelar emphasizes, "Then you have to ask the dog."

Some experts suggest having the child putting out a closed fist or a hand with palm upraised, others say just stand there. But all agree: Let the dog decide whether to approach the child. Don't hold a dog still in your lap for petting, and respect the dog's decision if it turns away or moves behind the owner.

• If the dog does approach, observe the body language. Don't concentrate on the tail — it can be hard to read. Pelar says, "I tell people that if they're looking at the tail, they're watching the wrong end of the dog."

Instead, the mouth can give a lot of clues. A dog that's licking lips, panting excessively, or yawning, is showing that he's not comfortable. These are oral self-soothing behaviors much like sucking your thumb, says Pelar. In contrast — opposite of the common maternal fear of the teeth showing — if the dog's mouth is open, that's a sign that it's relaxed.

• Pet a dog under the chin or along the neck or side, not the top of the head.

Pelar explains this to children by saying, "Avoid the sensitive eyes and ears." This is easy to understand, and the result is that they avoid the blind spot on the top of the dog's head.

• Encourage children to pet slowly, rather than rapid patting. "Slow motion like in the movies, every kid understands what that means," says trainer Amy Robinson, whose DVD "Drool School" teaches dog safety to children.

• You can also do some advance training to prepare your dog for social interactions.

Although children should be told not to pull ears or tail, sometimes they're too quick to stop.

So do desensitization exercises with your dog by touching or very gently pulling ears and tail, and then praising him. (Robinson says she doesn't use food rewards for this, so that the dog doesn't see children as a possible source of treats if they touch him in those spots.)

• Aside from watching out for your dog's comfort level, you may want to be prepared to gently educate. When explaining to children how to approach a dog, see it from their point of view.

" 'How would you like some strange person to run up to you, squeal, grab your face and give you a big kiss?' They get that, they understand that when you put it in those terms," says Robinson.

• If you have to say no because your dog's showing a stress-related behavior, take the opportunity to point it out. And on both sides, try to understand that it's not a judgment on the child or on the dog if this just isn't the right moment.

"If the owner says no, that's no reflection on the child's behavior," says Pelar. "That person is not saying that you're not kind to dogs. They're saying that my dog's not comfortable. And that's OK."