My pugs both lick Cinder, and Millie cleans Ralphie's wrinkles every evening. It looks like she loves him so much when she does it. And he has such a guy look on his face, like he loves her enough to let her. Even though it kills him to get his wrinkles cleaned. :laugh:
It's an instinctual adaption derived from a puppy licking an adult's lips and face to elicit regurgitation. Wolves and dogs do this as a way to release tension especially after a rough play time and so yes it's a form of bonding and affection. It's also normal communication to growl so just because they are bonding and showing affection and then growling doesn't mean they do not have a close relationship. They are just conversing with one another. Dogs live in the moment so the one being growled at will not hold a grudge or be angry. That one will just respect what is going on and move on and when the time comes for some affection they will freely give it to one another.
I haven't seen a clearly defined hierarchy between the two yet.. Koda is far more bold than tucker.. but i've always put tucker first.. first to eat, first to go outside, first for pets, rewards, etc.. but he's such a laid back guy he doesn't seem to mind too much that koda beats him to the door every time, pushes him out of the way to get into the bathroom in the morning, etc..
and when they play.. they both take turns of getting pinned to the ground, belly up and wiggly.. neither one seems to mind being submissive.. it seems to make for an easy transition..just don't touch tuck's paws =)
I agree with what's been said. Mine do this sometimes, seems like bonding/reassurance after playing hard. My two also take turns being the "top dog" when they're playing. I think Bo is still slightly more of the leader, but it's hard to tell. They just get along so well.
I thought I read somewhere that the one doing the licking is being submissive. Willy always licks Libby's face. She never licks him. She is older and we tried to teach him that she's the top dog in the housse, she was there first. I didn't want a dominate male again.