As with any situation where the assailant gives you a convenient limb to play with, I would suggest trapping, a quick painful distraction technique, followed by turning around beneath their arm ( while the hand is still locked in position). People tend to loosen their grip once their wrist is facing the wrong direction. Then, as you are still in possession of the aforementioned limb,do what you will with your recently acquired hand. I did this during practice when I had long hair. I had always been a bit worried about it, so I applied the same logic used in any grab attack. Like I always say, anyone foolish enoughto give you an arm doesn't deserve to get it back. (at least not in the same condition they gave it to you in) =^_^=