Fortunately, fire medic Jeff Rehman has a great method for saving your own life when things get desperate. Best of all—it requires nothing more than a solid floor.
Immediately get on your hands and knees in a modified "pushup" position. The aim here is fall onto your own chest, so position yourself accordingly.
Shoot your arms out in front of you so that you'll fall, forcefully landing on your chest and belly.
This will push air up through your throat, hopefully dislodging whatever is causing you to choke. Repeat if necessary to clear out the blockage.
As Rehman points out, this method is not foolproof, but in a desperate situation, it's a very helpful technique to know. To see a video of it in action, just watch below.