weird dog behaviour towards puppies

ever since we've got new puppies my oldest dog has been acting very weird around us. Most of the time when the puppies come near him he will run away, but lately that seems to have stopped a bit. Now when they come up to him they'll lay on their backs and he'll start licking their genitals. :shock: If the puppies were girls it would make a bit more sense but in this case they're all male, so I don't know why he keeps licking their genitals. He's (older dog) also taken up on licking their pee too. :shock:

Is this normal?!

 

How old are the puppies? It sounds as though he's doing the natural bonding thing, a lot of male dogs will 'adopt' puppies and take on the 'responsibility'of raising them. Its good for socially. Just watch he doesnt 'clean' them too vigorously.
I had a male cat, male dog and a female dog, take turns in cleaning a 4 week old kitten, cleanest kitten in LA but a little raw on occasion.

 

The puppies are almost two months, they seem to enjoy his licking too, so it's kind of weird haha. BUt that eases my concerns, thanks.