Abram often bumps into Ruby knocking her over . If we are sitting on the floor playing he will bulldoze his way in between us and knock her over a long with destroying what ever we are doing. He is careful never to jump on her ans if she is handing him something a toy or treat he is very gentle when when he takes it s o I think he gets that she is little. Problem is Ruby now kind of flinches every time he walks near her. How do I fix this