this normal?

So, um, the dogs.  They, um, like to lick each other.  Or rather, Moe likes to lick Porter.  I swear I read somewhere that it's a "pack dominance" thing.  She's the alpha so he has to groom her...or something like that.  Usually we just let them get on with it.

But, prior to yesterday when Sweet Husband captured this shot, I've never seen them in this particular position....Anyone?  Thoughts?