Writing about the Ribeiro escape from the rear mount a few days ago, I left out a key part of the escape.
In addition to blocking the choke, the other main ingredient of this escape is the "duck." This is when you scoot down into the rear mount so that your shoulders are below his shoulders. I did mention this (i.e., "get small"), but rewatching Saulo's video snippet made me want to reinforce the point.
You don't want to put your weight on him. That gives him control of your body, because your balance is dependent on what he does.
The other typical escape involves turning to your side and trying to unhook with your hands. Never try and unhook with your hands. Hand or hand/arm don't beat leg. Hip/body beats leg, though. So ...
You want your weight to be largely on the mat. If he keeps his hooks in, then he is blocked by your body from being able to do anything.
From there, shuck a leg and swing around the other leg (basically, swing around the hook that is still in). Whatever I do, I DO NOT want to try and swing around the leg I just shucked. This is classic jiu jitsu; using what was formerly your opponent's advantage into your advantage. So shuck and swing the other way. Worst case scenario is ending up in the guy's half guard. And we know what to do from there ...
Here's the escape. Choke defend with the thumb in. Then three moves to escape: duck, shuck and swing.
