My son had trouble with toilet
training in a similar way. He would sit on the toilet for an hour and not be able to "go". This problem worsened during the school year, both because he did not like to use the school bathrooms, and because if he had to go at an "inappropriate" time, the teachers would not allow it, insisting that the 20 minute recess and the 40 minute lunch break were adequate opportunities. This contributed to a severe constipation problem.