Poo goes to PooLand, video on YouTube about why poo needs to go down the toilet . I think they recommend emptying the filled nappy down the toilet and flushing etc to show them that's where it goes. Lots of praise and rewards, if he starts in his nappy, could you quickly get him on the potty / toilet to finish off? Does he have a poo schedule at all? After dinner? Or tea? Maybe see if you can track it a bit and sit him on a bit before and get him to stay there. Does he wear big boy pants all day?
Mine went straight to the big potty too. I feel like it takes practice and at this point it’s more about personal control than ability. It’s time to be done with the diapers and go to underwear. I liked the padded training underwear cause it helped catch any leaks or accidents and make them easier to clean. I would put him in charge of his body and his journey. Take him when he tells you he needs to go, and he is in charge of helping you clean up when he doesn’t go in the potty. We have been doing well that way. He had pooped in his underwear much more than I would have preferred, but he is getting there.
I’ve just potty trained my little boy (he’s 2 and a half) I read the book “Oh Crap! Potty Training” before we started and found that this reassured me massively! We stayed at home for 3 days with him naked from the waist down and then introduced trousers with no pants for a good week and then cause of no accidents we introduced pants! I had a travel potty and normal potty as well as steps for the toilet and just made sure all were visible and he had easy access! I made it worse in my head because once we started I felt better about it :) You’ll do great!
My biggest advice is do not stress!! I know it’s easier said than done. I started getting my son acquainted with the potty concept when he turned 1 and he didn’t start full use the potty until 3.5. I was stressing myself out way too much because almost all the kids around were fully trained before they even turned 3. My son resisted wearing underpants and still wore pull-ups until one day he agreed to underpants. And since then pull-ups were gone for good. No incidents. No pull-ups even for night time. He was ready when he was. Stay consistent, keep offering underwear and suggest to him going to potty often.