Did you know that dogs need to be introduced when meeting for the first time? It's best to leash them so you have full control of the situation. Not ALL dogs will get along with each other. If there's any snarling or growling, you can keep them apart until they settle down. Let them come nose to nose to sniff. You'll see them wag their tail, or possibly tuck their tail between their legs. If the tails are wagging, their probably going to be friendly with each other. They will posture, and sniff each other to "get to know each other". This is especially important for male dogs. They tend to be a little more aggressive with other males, than females. Take it slow.