Why does my back feel warm? and damp?

3 times in the past couple of months I have woken up with the feeling that something isn't right. One minute I am sleeping peacefully in my cozy bed, the next I'm wondering why I'm cold. There appears to be a small child behind me, taking up most of my pillow and stealing my covers.  Maybe that's why I'm cold.  But wait, my back feels warm, but cool at the same time, how odd. Wait a minute, is that dampness? is my shirt wet? How could that be? and what is that acrid smell?... Suddenly I am very wide awake. Arrrgghhh. He wet the bed. Good thing this little boy is so adorable.