My favorite way to train with Divo is to just go out in his pasture and train. Not lunging type training, but picking up his feet, teaching him to flex, to back, and to trot along side me with vocal and body cues. Laying on his back, hanging on his butt, playing with his tail, rubbing down his legs, etc.
I was last out Sunday and we made awesome progress with flex. When I quit for the day, you could stand by his side and give him a tap on the opposite side and say 'Flex' and he would bring his nose around and touch his barrel. Same for the side you're standing on. I alternated sides, left, right, left, right, to get even 'flex training'. We did it all without a halter or lead, just me and him out in the pasture, having a blast. He kept wanting to give me his head, determined that he would be rewarded quicker, but he did get it quite quickly that the only way he gets rewarded is if I'm standing beside him and he brings his head around.
I also did some small work with walking beside me without a lead, trotting beside without a lead, and we played hide-and-go-seek I'd 'hide' behind a tree, and he'd try to 'catch' me. Or I'd sprint to the next tree and 'hide' and he would come trotting over. At once point I dashed to the lower gate, and he went tearing off around the pasture at full speed, bucking and having the time of his life.
The sliding stops in front of me when I called him were a bit unnerving though. I'd whistle for him and he come BARRELING over and stop just in time. Lovely Divo, but a bit scary!
I don't consider this 'natural horsemanship'. At the most, I'd call it at-liberty training, tackless training, or training without aids. Does anyone else enjoy doing this with their horses? I find it to be quite fun, honestly. I worked him in between with a halter and lead, but I have the best time with just me and him.