This happened to me during the end of Summer in 2005. I have to say that I have never been sat on or had ever experienced something like this before.
I was visitng a friend in MN and one morning I had dropped her off at work and came back home because I was going to go somewhere and needed her car. I came back to her apartment and got myself ready and left. I didn't return home until it almost noon or a little after. I was tired, so I figured I lay on the couch and take a nap before I go and pick my friend up from work. Her apartment was on the second floor if i can remember correctly. I had the sliding door to the balcony opened. The traffic on the highway was obviously loud, and I can feel the light wind as it came into the apartment through the opened sliding door. I was laying down on the couch with my feet towards the sliding door. While I was slowly dozing off, I can hear the traffic and two little laughing and seemed like they were playing outside. All of the sudden, I could not move. I tried to open my eyes, but they did not want to open. All the while, I can still hear the girls talking and laughing through the sliding door from the first floor. I tried to move my arm, but to no avail. I tried to scream in hopes that the scream will break me free of whatever it is that is happening to me. The attempt to scream did no good either. After all attempts failed, I thought to myself I will give it one last try by moving my arms. I gave it all my might and with a hard jerk, my left arm with was on my stomach, finally moved. Once it moved, my body was back to normal. I stood up and asked myself what happened.
It was strange because all the while this was happening, i was fully aware of the sounds from the two girls and the traffic. I mean I can hear it clearly, and i didn't feel like i had fallen asleep.
I didn't tell my friend until after I came back home because she lived alone and I didn't want to scare her. After I told her, she started sensing that someone was always watching her. Whenever she's in her bedroom, it seemed like someone was watching her from the living room and vice versa.