While we are talking about good uses of thumbs, how about if an attacker grabs you wtih both hands.
A quick touch to both of his eyes with your thumbs will make him almost instantly release.

If a quick touch doesnt work then Im sure you know what is next. :0

I was think double lapel but you could adapt it to a 2 hand front choke.
For hand positon imagine if your holding a glass full of something.
Remove the glass.

The hands would go on each side of your attackers head and thumbs in the eyes.

Scott

Now you have it.
Correct me if I cam wrong but I believe the pressure point in the eye is on the heart meridian so it should lower the heart rate, possible setting up other points as well.


on edit...
Correction. The eye point is not on the heart meridian. I just confirmed with Master Lambert.
However it does lower the heart rate and many other bodily functions as well.

Bladder 1 is in the inside corner and 2 is right above it on the brow.  St1 is just below the pupil.  TW3 is on the outside end of the brow, GB1 is on the outside corner of the eye.  There are a number of ways to set up a knock out.  That's why I like arm points so much, I can't reach you so I gotta bring you to me.  I like  to "embrace" my attacker! 

Strike L5 with a hammerfist, with a twisting motion, toward YOU.  Now hit St1, 2, or 3, you will probably hit all three with a fist, but pick one if you're using your thumb. (I did this one and it worked great.  No ko, but the guy couldn't see and had to sit down!)

Strike P4, 5, 6, and 7 with a shuto, raking downward toward you.  Then Stike TW23.  I personally would use an uppercut or palm heel, upward and outward.  For GB1, same, but ridge hand inward and slightly toward the back of the head.

 To set up B1, you would have to grab your attacker's wrist after he has grabbed you, put pressure on H4, 5, 6, and 7 with all fingers.  Then you can use your thumb or the thumb fist in toward the nose and in toward the tear duct area of the eye.

These are VERY incapacitating shots.  If Mr. Bad guy doesn't go down like a ton of bricks, he will be stunned, crying because that's what happens if you get hit in the eye, and probably fall down, but consious.

I don't think I'd hurt my thumb on soft tissue.  I just wouldn't use it near a bone like the knee or elbow or ankle.  Thumb strikes are not practical for me to use on the eyes because I have to do so much to get you close enough to do it.  I like thumb strikes or the thumb fist strike.  It's just not practical for me.

The film of the martial artist that knock the pip scentless was a high block-strike just under the jaw as shown in any basic kata. but the fist wraps around the neck. This type of strike lifts the jaw at its hinge and disrupts the nerves in and around the hinge. it is classified as a cavity strike not a pressure point but in reality it is a kind of a joint lock to the hinge of the jaw. I say that to show that the jaw is pull outwardly by the twisting of the high block(strike).

I SHOW THE BEST ONE ON THE CLINIC ONE DVD .