No suggestions, but my 9 year old Stafford is merely a tongue with eyeballs and feet. Whilst he will try to lick your face, he mostly just licks arms and hands. Anyone who comes in the house gets a good washing unless you shove a toy in his mouth, then he wanders around "talking" and wagging him bum.
Hes quite a submissive dog, although hes not a roll over and expose the belly kid of dog, i think due to the fact that he gets quite anxious and panicky.

Aslong as he leaves my face alone, i dont mind. If guests dont like it, then the dogs are shut out of the room.