I have a 7 month old blm who I have been working with. Obedience is good, Sit, Heal, and Here. I have been trying to get holds solid and haven't had great progress. I have tried different bumpers, Dowels and dokens, but I don't seem to be getting through to him. I have been working on holds for at least a solid two weeks. I can get him to hold for maybe a minute or 2 and then he starts fooling around with it and drops. Any suggestions??