We've had our 9 week old labrador puppy for nearly a week now and he is settling in a treat. His crate training is going brilliantly and he is a dream. he comes from a good strong line of working dogs and so I would expect a degree of intelligence!!! But, now that he is getting more confident in his new surroundings, he has taken to launching himself at us and biting. This happens especially at times when he is playing ball games, rope games etc with us. I have tried growling, barking and yelping but it seems that this won't deter him. How can I train him out of this sooner rather than later?