Holy shit, what a fantastic video. Love how you go from completely soft to rock solid, and how you start ejaculating the instant you are fully erect. Magnificent!
This video explains what would happen to me at 11 and 12, a few times a week while asleep, and I'd wake up with a sticky mess in my underwear, and (at the time) no knowing/understanding what was going on. I didn't realize I was already ejaculating, and needed to start masturbating earlier than I realized. Once I did start, I watched my dick go through these phases, except it was happening with my right hand, no longer without my not vigorously stroking it.