Alright, you’ve got a well-trained dog. However, you failed to socialize him as a puppy, and he’s a bit stand-offish with other dogs. Because of that, you are afraid that there will be a dog fight. Having a large dog might pose a problem. Small dogs are also dangerous when they are aggressive.
This is only a rough guide for dogs that aren’t aggressive. If your dog shows any willingness to bite another dog, don’t hesitate to contact a professional. It’s best to admit that you need help with your dog than to have him put down for mauling another person’s pet.
Things you can do to socialize them:
1. Take them to parks/busy areas with people/plazas/shops (be sure you are not just walking them there but training them there!) Keep them inline at all times! Make corrections!
2. Dog parks
3. Neighbors houses (be sure they behave, do not just let them run around. Remember this is training not play time!)
4. Sporting events (soccer games, baseball games, skate parks etc)
5. Special dog events
These are a few places to socialize your dog. Do it early, its important for later!
Kenzie at a Indoor Soccer Game:
**some info from this blog has been taken from http://www.wikihow.com/Socialize-Your-Dog