I have come across a problem with my dog. Almost all of the training I do with my dog is with just her and I. I hand throw 99.9 percent of the bumpers she retrieves. Lately she has been taking her eye off the bumper I have just thrown before it hits the ground and looking back at me almost like she is waiting for permission to retrieve it. It is really effecting her marking ability. I tried to correct it today by making her sit on one side of my truck while I walked around the other side (out of her view) and threw bumpers for her. It seemed to work but I am wondering if there is a better way to correct this behavior. She has been doing it a lot lately. Any suggestions?