I promised awesomeness regarding this technique tonight, but it will be delayed. I shall include pics and/or video as recompense for my lateness.
Ok, so I previously talked about this technique over on Bullshido trying to determine whether it was a viable technique or just something that was working on total noobs. Wednesday night I pretty much answered that question by tapping our senior blue belt who outweighs me by 70ish lbs with it. He was unable to pressure up against it because of my shin pushing on this throat, was unable to push my leg off of his head because it was secured on his neck, and was unable to pry my foot off with his other arm because my other leg was able to push against his elbow. Pushing with my shin allowed me to force him to release his defensive grip on the armbar to try to relieve the pressure on his throat, which allowed me to isolate the arm and finish the armbar.
I included this technique on my recent mindmap as an attack from mount and from guard. I was asked if it should be linked to the Omoplata because it is applied from an Omoplata setup. The answer to that is that it CAN be linked to the omoplata, but I rarely hit it from there. I most often hit this technique from guard only if my opponent postures up while I have their arm and am trying for a traditional armbar.
More commonly I hit this from the top. I go to the traditional armbar and then immediately rotate my hips and wedge my shin into the throat. I find it gives me more control and allows me to put more pressure on large opponents that normally are able to resist my armbar attempts via brute strength.
The pressure you can put on the throat is enough to cause SERIOUS discomfort because the shin is driving UP towards the top of their head as well as down towards the floor. The pressure ends up being applied to the area of the throat JUST under the jaw, if you press against that with your hand a little you'll see why it's so effective.
I've had a couple of people try to defend by reaching up and grabbing my foot to peel it off their neck. To stop that I use my other foot and stick it in their elbow and push away. This also keeps them from turning up into me to try to hide their elbow and escape.
If your opponent is strong enough they may still be able to sit up, if that happens don't worry. Just keep your leg extended and apply pressure on the arm across your thigh for the tap.
A note of caution, your leg is assisting this technique, so it applies more pressure than just pulling with your arms. People are likely to tap before you think they should.
This technique is great if you are a smaller, weaker guy who has a hard time breaking the hulk smash grip of your larger opponents when they are defending the armbar. If you are generally able to get to the armbar position, but can't finish it before your opponent escapes this is for you.
Step 1. Get to your basic armbar position from mount so that you are on top. I hit this from scrambles a lot when people stiff arm me to keep me from passing.
Step 2. Scoop your opponents arm with your arm that is closest to their feet.
Step 3. Turn slightly up on your side facing the opponents head and post up on your elbow.
Step 4. Rotate your foot so that your toes are pointing at your opponents ear. The closer to that exact angle you can get, the better.
Step 5. Open your hips and push your shin into your opponents throat.
Step 6. Start your grip breaking. Put your other foot on your opponents elbow or bicept and push, you should be able to angle the push so that it puts more pressure on your opponents throat. If this fails go to step 6a.
Step 6a. If you can't break the opponents grip and they haven't released it to attempt to defend the throat yet then take the flat of your foot and place it on the heel of the leg that is pressing against their throat. PUSH DOWN. This might tap your opponent here, but it will definitely make them release their arm.
Step 7. Now that the grip is broken use your other arm to hook their arm at the wrist and place your other leg against their elbow to keep them from regaining their defensive grip. Slowly work the arm straight against your bottom thigh.
Step 8. Remove your foot from their elbow/bicep and place it on the ground near their armpit. Use it to arch your hips up off the ground while you push the arm down for the tap. Alternately now that you have the arm extended you can switch to a more traditional armbar position for the finish.
Now, if you find that for whatever reason you just CAN NOT make them let go, no matter how much you mess with their throat you can scoop their elbow with your other arm, the one near their legs, and post up onto your hand. Work your way up to the mounted Gogoplata position and finish from there. I've yet to find anyone I couldn't get to release their grip with the shin in throat method though.
Illustrative pictures will be posted when I can get some taken.