Justine, F used to do that too - she didn't have many bad gagging experiences, but she used to flail her arms wildly and we knew that meant she had too much in her mouth and didn't quite know what to do about it. But she learnt, and now she usually knows not to put in so much (unless it's something REALLY yummy like watermelon or mango, and then she sometimes forgets). I think it might be a phase they have to go through at some stage. It is scary, but I would always just sit right there with her, and try to speak calmly to her - have you got too much in your mouth? You can take some out... sometimes she would get a bit red in the face and teary, but I was always sure that it was gagging, not choking. And she's usually not upset at all afterwards - she just reaches for something else. So I think follow I's cues in that regard too - if he's upset, maybe it was too difficult for him for now. If not, it was just a learning experience.
Creations, I use the same dough for my pizza dough as when I bake bread. I got the basic recipe from here:
http://www.annamariavolpi.com/pizza_recipe.htmlbut have adapted it, so I use about 1/4 cup of oats (the instant kind), 1/2 cup of rye flour, 1/2 cup of wholemeal flour, and 2 cups of white (more as needed). The trick is to leave the dough stickier than you're comfortable with when kneading - it's tempting to keep adding flour til it doesn't stick to your hands, but don't! When making a loaf, I leave dough to rise, punch down, put in loaf tin, leave again for half and hour and then bake at 180 degrees for about 35 mins (depends on your loaftin. or you could do it without a tin, just on an oven tray).