Falls happen anywhere in reality, but when you want to fake a fall, you may need to practice. The easiest way to fake a fall is to trip yourself as you are walking. Slips and slides are harder to fake in the real world.
Trip yourself up as you walk to fake a fall. As you are walking, step one foot in front of the other. Make sure to place the blocking leg far enough in front of the other leg to trip yourself safely.
Raise your non-blocking foot to take the next step. To fake a fall with some realism, you must continue the momentum of your walking up to the trip to help you actually fall.
Catch the raised foot on the ankle or calf of the blocking leg. Try not to catch the blocking leg in the back of the knee, as this could bring you down more quickly than intended.
Brace your fall with your arms. To fake a fall, and avoid getting hurt, you must bring your arms down as softly as possible.
Bend at the waist to place your hands on the ground safely. The momentum of your walk should help you get the quickness of the fall you need to make it look real.
Bring your butt down to the ground. After practicing many times, you can fake a fall with minimum to no harm to yourself by bringing the butt down last. This way your arms can brace the fall, and your hip or buttocks can meet the ground gingerly.