Re: Need Ideas for going poop on potty!
What's 4k? Do you mean he is 4 years old or in 4th grade...? That said, there is a lot of helpful information in this book called "It's No Accident" by Dr. Steve Hodges. The book is about kids who have pee accidents, but it talks a lot about bowel holding (apparently a lot of pee accidents are actually the result of complications from bowel holding).
While control is certainly a big issue with young kids, I'm thinking he may also be afraid. As a former holder myself (and the mother of a young holder), all you need is one bad experience with constipation...
*Insert list of crunchy mom stuff here*
ISO Zutano and a Ponyo DVD, IHA 2t Antsy Pants and size 1 Piddle Poddle trainers