Hi, My 9 week old puppy doesn't seem to be getting the message when I say "NO!" What is the best way for me to ensure that he gets the message as quickly as possible, for instance, when he is trying to jump up on the sofa or he is nipping? I've heard about banging something like a newspaper or using a water spray but not sure I want to go down that route really. Any tips that can reinforce my "no!" Message will be gratefully received!!!!