After taking a lot of slack for using a prong on Cody, I was glad I stuck to my guns. He was so powerful, I'm lucky my arms are still attached to my shoulders. I got the correct fit, and only used a tug sparingly. because he caught on so fast too. Within a few months, he walked with a regular collar and leash. Not always a perfect gentleman of course, but it seemed that quick tugs did the trick most of the time. Anyway, sounds like you and Ajax had a great time! What a smartie pants!