F.G.
I've said it before, and it always works like a charm. Get EXCITED about poop! A lot of children have anxiety about pooping in the potty because we, as a society, look at poop as a negative thing. When they're babies and they poop in the diaper we say "ooohhh... stinky diaper!" Of course, that's natural because we want them to know that we don't like poop, and not to touch it or stick it in their mouth (heaven forbid!!). However, by doing this we create an anxiety for them and it becomes hard for them to poop in the potty which isn't as private as a diaper to them. But, if you get excited and say something like, "I'm so excited about your poopoo! I can't wait for you to poop! Can you poo-poo in the potty so that I can see it?!! That would be wonderful!!!" Or whatever comes to mind. Then just leave him be. If that doesn't work immediately (which it usually does) just keep it up until they are CONVINCED that you are genuinely happy about poop, and then he'll poop in the potty to make you happy. Good luck.