I had something similar with my younger boy (now 6). My first suggestion would be to take him to your GP (or consult GP without him there if you don't want him to get worried about it) but if there's nothing medical wrong unfortunately in the end the only thing that works is saying absolutely nothing. Not being cross, not saying a word, just clearing it up without saying anything and then acting as normal. Believe me I know how hard that is. I usually took it out on my poor other children after the insane amounts of patience it took. Good luck.
my little boy has been potty trained since before he started nursery last September. We started late since i didn't he was ready but he got using the potty and toilet pretty much right away with the peeing. But he has never gotten the pooping. He isn't scared, i think he is just lazy but i don't know what to do. He is almost 4 now! there are days he'll go 5-6 times. I've tried rewards, punishment, yelling, saying nothing and even having him clean up himself so that he sees how much work goes into it. he doesn't care! Please, can someone help me? Anyone?!