If he is kneeling directly on your legs he should be unstable. You should be able to bridg out. If he is mounting you - sitting on your legs with his knees on the sides of you, holding one arm to the ground. I would block my face with free hand, do not let him grab that hand. quickly try to slide the hand he is holding along the ground to a position strait over my head. He should lean forward a little, letting off your legs. Quickly bend both of your knees, trapping his foot/leg with your leg (on the outside of his) on the same side of your body that he is holding your arm on. Use your other leg to push on the floor and bridge to the side that you have his foot traped on, at the same time quickly slide the hand he has a hold of (which should be over your head) 90 degrees strait out from your body. If you can follow the instructions try it on a partner. It works for me O - He will try to catch himself, he may let your arm go, you can grab it and pull toward you and bridge again.. the point is to keep on trying. he will open himself up.