Hi, my three year old son (almost 4) is a very normal, social, chatty boy. However, he seems to be obsessed with trying on an old tiger costume we have in his closet. It's a size 2-3, so it's too small for him to wear for Halloween, etc. We are curious to know why he goes off by himself at times and tries on the costume with the bedroom doors closed. When I come in to check on him or see what he's up to, he immediately starts taking off the costume and says he doesn't like it and doesn't want to wear it--almost like he's getting caught doing something bad. I tell him it's ok for him to wear it and tell him he looks cute in it. He says, "no, no, I don't like it." When I leave him alone for a bit longer, he puts it on again and seems to enjoy wearing it (I peer through a small crack in the door to watch what he's doing). He reacts the same embarrassed way when I come in again. What do you think this is about??