I do not think that holding the leash and dealing with the dog is the best situation for getting an overall fluid barefoot running form. Now that my mileage is increasing, I will probably be dropping the dog off at home after about 3 miles, and continuing on without her. That's what I was doing last year when I was run/walk training for that 1/2 marathon.
Some of my ideas about form have come from the fact that I was enamored of Chi Running, propogated by Danny Dreyer. I was studying his book and trying to teach myself the chi running form when I was wearing shoes. So, even as I barefoot run, I still keep in mind and have been influenced by some of the idea in the chi running form.
For example, one specific idea that resonates with me is that the running form is a whole body form. I like the idea of being propelled by an agitator-like motion of the core.
Well, anyway, as I was running along, hands free, the idea occurred to me to use my hands as a kind of reminder to my feet of what I wanted the feet to do. I began to kind of mimic the light fluid motion I wanted in order to "tell" the feet how to land and how to lift.
I remember when I took my first barefoot running workshop in Central Park with book author Michael Sandler (Barefoot Running: How to Run Light and Free by Getting in Touch with the Earth). I think I remember that he mentioned that the feet do what the arms do. He said this when explaining not to let the arms swing across the body, but to have them swing straight forward and back the way you wanted your feet to go.
With this in mind, I thought maybe my feet would follow my hands if I made a motion with my hands that I wanted the feet to have. I used a kind of swimming motion with my hands as I ran along. Any time I was getting tired and starting to lose form or tread a little more heavily, I would remember to start this swimming motion with my hands and it helped get me back on track.
Because my arms and hands are not coming into any contact with the ground or forces from the ground, they are able to relax and have that "noodle-like" feeling that I think I remember Jason Robillard -- author of The Barefoot Running Book -- described. The feet can then follow suit.
I have tried to make a little video explaining this which I will post below. The limitation of the video is that I'm running in place and the arms are not swinging like they would naturally from the forces running motion would exert on them. Also, I'm not as relaxed in front of the camera as I am when I'm "out there."
Oh, and despite 6 takes of this video, I kept chopping off my feet in the picture. I had my feet in the first two videos I made, but then there were other things wrong and I kept re-doing it. What started as a quick-run-out-and-make-a-little-video was turning into a "project" and I didn't have time, so I just went with the best I had up to that point. Probably one more take and I would have had the feet in there as well. But I think the point is that you can tell from what the rest of the body is doing what the feet are doing. And that is the point.