I haven't had that for years, but it happened frequently when I was little. The sensation of things touching my face, pushing my shoulder, or especially pulling my blankets off me. Being unable to yell above a whisper. Waking up with my blankets at my feet, or already sitting up. Not to mention sleepwalking. Until you've had the shock of waking up in some other place, you don't understand scary it is. You try to just go back to sleep where you are rather than deal with the horror.
What I needed was someone to tell me that I can stop them by not being a party to fear, that they are fear and are drawn by fear and can't bother me if I don't participate in it.