I had something similar happen to me once. I was trying to use the law of attraction to attract a girlfriend. And as part of my process I would fall asleep with my arm around a pillow imagining that it was my new girlfriend. Like they say, you have to imagine what you want as if you already have it. So that's what I was doing. Anyway, I feel asleep like that and experienced sleep paralysis and it felt like someone was behind me and put their arm around me. Scared the **** out of me because I was sleeping alone and since I was in sleep paralysis I couldn't move.

I believe we leave our bodies a little while we are sleeping. And once you're in sleep paralysis it's very easy to leave your body. So what I think happened is that my astral body floated over to where the pillow was at that I had my arm around. So my physical arm which was around the pillow was also now around my astral body. And experiencing myself from the astral body It felt like someone had their arm around me. Just didn't realize at the time that it might have been me.

Could have also been a spirit I guess, but I doubt it. The only time it has ever happened was the one time I sleep with my arm around the pillow. Won't do that again.