Stand behind the person who is choking, and wrap your arms around their waist. Make a fist with one hand and place the thumb side of your fist against the person's upper abdomen, just below the ribcage and above the navel. Grasp your fist with your other hand, and press your fist upward and inward in a quick and forceful manner. Repeat thrusts until the object is expelled or the person becomes unconscious. If the person becomes unconscious, lower them gently to the ground and call for emergency medical services. Begin CPR if necessary, starting with chest compressions. Note: If you are performing the Heimlich maneuver on an infant or a pregnant woman, the technique will vary slightly. It is important to seek proper training and instruction before attempting the Heimlich maneuver in any situation.