Defense to the ultimate armbar defense

Using this tonight!


had a visiting white belt try the original arm bar defense on me. he told me when i was trying to break his grips he saw the defense online and he couldn't be arm barred. i didn't have the hear to say anything so i just tugged and he tapped. Phone Post


Sub Phone Post



In. Phone Post


I remember having someone in an armbar and they did that same slap thing,  I let go immediatly from the shock.

Is this a legit tecnique?  Is it like...taught???