Grooming Behavior

Unfortunately I don't have a picture to go with today's post because I cannot seem to get a picture of what I'm seeing.   I was wondering if those of you with two or more dogs have seen this behavior.

Bonnie and Bailey... in my opinion... have bonded.  They play together, they never fight, they lay next to eachother whey they are outside and inside, and they do this very weird thing where they sort of chew on eachother... or at least I think that's what they are doing.

You know when a dog has an itch and they start that rapid biting that looks to be a way to stratch places they can't quite get their hind legs on?   Well that is what Bonnie and Bailey are doing to eachother.  Are they grooming?

It usually starts in the middle of one of their neck and nose and ear biting play sessions (some vocalizing and lots of running around and taking eachother to the floor).  One dog is the bottom, on his or her back, and the dog that is growling and play biting the other's neck will stop and then start doing the rapid scratching/chewing on the other's neck.  The dog recieving this behavior (fairly equally Bonnie to Bailey and vice versa) will just sort of lay back and let the other one do it.   Then suddenly, as quickly as it starts, it stops... and play resumes. 

Has anyone seen this before?  Is it grooming or am I crazy?  They do it all the time and they seem to enjoy it about as much as they enjoy liking the insides of each others ears (which I think is totally gross!)