Good for you for recognizing that Reesie has a problem. Dealing with it now can keep it from becoming full blown aggression when he is an adult.
What Reesie is doing is called "resource guarding". You need to take charge of the resources. I highly recommend the Nothing in Life is Free program.
Nothing in Life is Free Nothing in Life is Free Gaining control of your dog humanely Dogs: Positive Reinforcement Training : The Humane Society of the United States