Problems pooping

I started to potty train my son at 2 years and 4 months.  Once he got the hang of it (in a few weeks) he was peeing and pooping on the potty.  It was kind of difficult to get him to poop on the potty, but eventually he would do it.  What he would do is sit on the potty for a second or two and say he was all done.  He would do this over and over again every few minutes so we knew he needed to poop.  He would also dance around to indicate that he had to go.  He always pee'd on the potty.  After 2 months of doing this he just stopped.  Now he won't even tell me when he has to go poop, he just does it in his pants.  I have tried incentives with candy, stickers and the promise of getting a new toy if he goes poop on the potty.  I'm tring not to push him too much, but I don't know what to do.