New addition to the family - a PomChi

Just last week we adopted a new dog from a shelter. He is a 2 1/2 year old chihuahua/pomeranian mix. He's supposed to have one bad flaw...he snarls and snaps when someone tries to move him - or looks at him if he is settled comfortably where he wants to be. In fact one of the reasons he was given up to the shelter was that he bit someone for just looking in the direction he was settled in. We seem to be making progress in ridding him of this habit. Mostly, we simply say, "Dusty, NO!" firmly and say, " Bad dog!" to which he usually stops the snarling. A couple of times we have used a spray bottle of water which Dusty definitely doesn't like. He stops the offending behavior and slinks away from the spot he was just defending. The snarling episodes are getting to be less frequent. He really is a soft fluff ball who loves to be held and babied. He loves nothing better than to be held all day.