sorry he's 4 now I see I ommitted that information
How old is he? My year old wouldn't go on the potty and would hide, we tried everything from stickers to fireworks.. (pop its) Nothing worked. I took him to open house at his daycare, the teacher in the "big" class told him he'd have to stay back in the "Little" class because he isn't having bowel movements in the potty, I can't tell you how many packs of undies we went through. The whole summer he was in "Big boy" undies nothing worked.. then low and behold 2 days before school started he said " i have to go poopoo in the potty" and to day we haven't had an accident. he chose when he was going to do it.. be patient he will on his terms
good luck!