Hi! I'm new here.. I have a 10 mo shepherd pup. He is pretty well trained and super smart. He follows most basic commands (sit, stay, goes to the door to potty, etc.) but for the life of me I cannot get him to stop jumping on anyone who walks in the door. I also have an issue with "biting." I use this loosely, because its not an aggressive bite, more of a "hey give me attention!" soft play bite... but he does it constantly.. even when I am giving him my full attention. I have tried basic tricks I used to teach him other commands but he's stubborn with this. I've read that it's a dominance thing and I should use stern, short commands like "NO" and "STOP" but that hasn't worked... Any tips?