This is an old dream that is pretty vivid in my mind because it was so disturbing. It happened when I was about 12.

A girl with long flowing hair (possibly brunette) and I are having sex in the middle of a dark room with me on top. The only light in the room is a TV on my right side. On my left side are three recliners with people in them. My mind said they were her family members. One was cheering me on saying stuff like, "Good Job" and "You can do it". The other two just watched the TV. I can't see the walls but I know that there is an interior corner behind me and the room is shaped something like Nebraska is. I don't orgasm and neither does she but suddenly the vision in my mind zooms out up to the ceiling and I see a pool of blood on the floor near our crotches. Again my mind said that this was because she was a virgin which I really didn't understand at the time. I also had the feeling that I was 15 and she was 15.

This really scared the shit out of me. My curiosity when awake made me ask questions about the blood. A friend of mine in high school told me the rest and that scared the shit out of me more.