I want to be a dog

My son was having trouble going to sleep. Sometimes he sneaks out of bed. I thought I heard him around the dog's crate but dismissed it because he wasn't laughing. I went to check on him, of course he wasn't in his bed. I checked the dog crate, and found him in there cuddled up by the dog. I told him he couldn't sleep in there because it was dirty, and he said, "but I want to be a dog mommy."