Some time ago we enjoyed a meal with some friends, and the children and adults happened to be eating in different rooms. Near the end of the meal, my friends 10 year old boy came in to inform me that my 3 year old son had just ate a napkin. Without much hesitation I replied, "All my children eat napkins when they finish their meals. That way when they sit down in the bathroom they don't have to wipe, because the last thing that comes out is a napkin."
The 10 year old titled his head thoughtfully and concluded, "Oh." He promptly left the room.
I looked over at my friend, the father of the 10 year old, with a smile and said, "You'll have to explain that one later."