In my very early teens I would occasionally be lying on my stomach rubbing against my mattress and feeling really warm. However I did not ejaculate. This was followed by rubbing against my mattress during a "dream" and cumming. I never recalled what the dream was about. Then it went to a semi-awakened state and lying on my back. Instead I would be using my hand and again it would end in an emission. The next thing I figured "I could do this when I am awake" using my hand and voila' - ye ol' masturbation.