like Giselle said its normally a sign of respect, my dogs do this all the time, only all my alpha dogs HATE being licked by the subordinats so it winds up in a circle, say Happy licks Misty, Misty get mad because she hates that then Happy gets upset cuz the alpha is angry with her so she in turn licks more franticly...its an annoying cycle in my house, and the only way to stop it is for us to step in between then and tell them to quite lol