Use Your Hips and Legs To "Get Him Off!"
If an attacker is lying on or straddling your hips, plant a foot and buck him off or trap his lower leg and roll, while simultaneously attacking the face. If an offender is to the side of your body or sitting on you upright, you might be able to hook his head or shoulders with your leg(s) and slam him down. Remember: your goal is to facilitate escape, not force him into submission.
Use all available weapons
Self defense means adapting and expanding, not restricting, our options. Learn to see and think about using everyday things as weapons. On the way home late at night, stop at a convenience store and pick up a cup of piping hot black coffee. After parking, pop the lid and walk home with coffee in hand. If physically assaulted, throw the hot coffee in the face of the attacker. Similarly, handfuls of dirt, noxious household products, or your fire extinguisher when aimed at the eyes of a violent aggressor could buy you enough time to escape or get help. Almost any item that has weight, mass, edges, or points can be an improvised self-defense tool when used against a vulnerable target. The list is endless Furnishings and objects may also become protective barriers. A briefcase or garbage can lid may be used to fend off a knife attack.