C.S.
Boys seem to have this fear much more so than girls. Something about having the external organ. My two older boys were potty trained early, next 2 didn't go poopy on the potty consistantly until 4yo. I wasn't really pushing it either, but that is when they were ready. I think that the busier the lifestyle the harder to accomplish such a big thing in their little lives. I just know from experience where there is fear on any issue you have to back off and leave it alone, and they usually come around in their own time. I hope you find what works for you.