I have a 3 year old, fully potty trained now. Her and I went thru this same issue. Everytime she would go poop in her potty chair, she would fight me when it was time to get off the chair. As we are lying here in bed now, i ask her why she did this, she tells me it was because she was scared of her poopy. when we were going thru this at that time, there were times where i would remove her from the potty myself which was usually a countdown... on 3 it's time to stand up and i would take the potty, dump it real quick so she wouldn't see it. i hope that this helps. think about pooping for the first time, wouldn't it be scary to you, ha! the first time my child pooped she said it looked like a puppy! i could go on and on about her becoming comfortable with pooping. just be positive and offer lots of encouragement!