Won't go poop!? Help!!

Countrygirl0289

My 2 an a half year old, pees just fine in the potty now but before peeing he only pooped in the potty most of the time. But in the mists of the change to peeing in the potty too he stopped pooping in the potty and went and hid and pooped in his pants. I'd catch him and move him to the potty and he got better at hiding he was pooping and just did it then would come tell me. Now he will pretend to poop in the potty get down and do it in his pants in plain site. Today we drank milk and stood up and pooped... After sitting on the potty. I have used sweets as a reward when he on occasion (rare) like once a month or 2-3 times a month, but ived Used toys, going to see the fire station, and he wants a bike really bad but refuses to go in the potty even though he will "pretend" to go. He will sit and flush and come say he pooped and I'll help him wipe of course there is no evidence of the deed... But in 5 min or less its in his pants praise doesn't work, ignoring to deed in the pants doesn't work... I am at a loss for what to do! Help please!