I couldn’t believe it!  It scared him a little bit, he cried for a second while sitting there pushing and then he got a little scared of the result…  I praised him endlessly and made a whole big deal of it, we flushed it together in the “big kids potty” and after all that he did a little dancing in celebration.  He was, in the end, very proud of his work.  I guess it’s the only time in life that we get to celebrate poop, so we must do it well.