He has a few indoor tennis balls that we toss around the house for him throughout the day. He will bring them to us to play fetch, or just amuse himself by bouncing them around the kitchen or down the stairs. When we are watching TV in the evenings, he will bring the ball right up to the sofa and then push them under with his paws. He can't get them out himself so he barks at them, does the play bow, etc. and when they don't come out "by themselves", he starts to chew on the sofa. This gets an immediate response from me, fishing the ball out for him, which pleases him so much that he does it all over again. So much for a relaxing evening of TV! It reminds me of when my kids were babies and they kept dropping things from their highchair just to watch Mommy and Daddy pick them up. I know I am reinforcing his behavior, but short of redesigning my sofas, I don't know how to stop this. Any suggestions?