These dogs know and trust each other. They also look out for each other: A dog who excessively licks the muzzle of his canine pal may be doing this because the dog has a tumor, cut or other medical need that requires attention and treatment. Puppies also "kiss" their mothers, but it's not a gesture of affection. read more
When dogs lick each other's face, they're not exactly kissing. It can be a sign of affection, but more likely, it's a sign the licker wants to play or is busy setting the social order. read more