What explains what I heard last night, when he was, for a lack of better words, aroused by playing like he was a toddler in a poopy diaper and saying to his mother during this play that he didn't want changed? On further note, I must say that, shortly after returning to our home after Christmas, we had Matthew tested, and he doesn't have any behavioral issues, developmental problems, autism, etc. He is doing well in school, but he just likes, for some reason, to play like he is a toddler in a dirty diaper based on what I heard him say during his play last night. So again, what should we do? Do we buy him diapers and put limits on where and when he can engage in this behavior? What is the answer here?