We haven't had to use a physical leash for the past few days. He is actually defaulting to a heel position if he has any question in his mind about what he is supposed to do. Once today we were walking down the driveway and I had to holler at Kylie who was being naughty and Wally (who was trotting happily about 20 feet ahead of me) stopped and actually walked/hopped backwards until he was in the heel position. He got a hug for that because he wasn't even in a command at the time.
I am having so much fun with this little guy!