This is when you are asleep and you feel something is on top of you, pressing you down. It is a temporary inability to move or speak that takes place when you are waking up or falling asleep. In this situation you must:
Keep calm and do the following:
With your hands make intention to grab the thing that is on you even though you cannot move, shape your hands as if you are holding onto it, as tight as you can.
Then start reciting whatever you know of Quraan or say Bismillah, Allahu Akbar, etc. in your mind until your tongue is free, then recite with your mouth, you must hold tight onto it and keep reciting preferably Ayatul Kursi until it dies or runs away.
Recite with an intention to fight, kill, and destroy whatever it maybe.
If it happens again repeat the steps above.
InshaAllah, once they know you can do this, they will stop.