Pooping only in a diaper/pull up

Kelsey • I like memes & gifs. 🤷🏻‍♀️

Help. It’s been a long time since posting on here, but I’m at my wits end. My 3 year old boy is fully pee potty trained. Even wakes up most nights dry. However, he will only poop in a pull up or diaper. He will throw a fit if u put him on the potty to poop. We have tried everything. Sticker charts, treasure box, candy, praise, tough love & bribing. I’ve even tried to put wait him but he ends up constipated & we’ve had to do clean outs to fix it. I need help.