I have a wonderful male, Blenheim Cavalier named Carter. We got him at 10 weeks and are thrilled with this breed (we had labs and golden retrievers before). Carter has always been a great pup and still is, however, I have noticed that within the last few weeks he has gotten very "excitable". He wants to play tug-a-war (his favorite game) ALL the time and has gotten rather rough in his effort to "grab" the sock. He has also started to sit and whine/bark at me when I am busy and can't play right now. I know as a puppy he needs a lot of attention and wants to interact with me often, but how do I teach him that he needs to play by himself for a little while?