I didn't go into a ton of detail above but I would have greenbean wear his diaper with his clothes over it (which is how he used to like to poop) and told him he only had to just put his but down on top of the toilet lid and then get right up. I demonstrated and made it silly and funny for him. I did some squats to show him in a funny way how fast he could be. then he could jump up and run away to poop in peace. After a week or two of that I asked if he would sit long enough for me to run around the house singing a goofy song. It was less than 30 seconds i think. I sang it really loud and in a silly voice and when I got back to the potty, he could get up and run away and poop.
That is how it started. I made sure he was comfortable sitting there. The room was warm and clean and he had a step stool to rest his feet on while sitting there. He always had the option of playing iPod/ipad games when he was there- even for the 30 seconds it took me to run around singing. I always had to make it fun and silly and stressless. It's so hard, isn't it?