Seven year old boy holding his poo in?

First of all make him an apt. with his regular Dr., and discuss it with him. Then make him an apt. with a Pediatric GI Dr. This REALLY REALLY sounds like a clic case of Encopresis. This is a condition where they hold it for many different reasons, and their bowels become overly full and overflow into the underware, they are completely unaware that it is happening and/or that it has happened. One of the clic things that brings on a "flare up" is stress. Please do not subject this little boy to pull ups, it will really diminish his self of steam.