Grab the pinkie of the individual if possible. The pinkie is the easiest finger to break.
Grab an individual finger, if possible, if you can not grab the pinkie. Grabbing multiple fingers distributes the force of your pull over more area, making it more difficult to cause a break.
Move the finger you have grabbed quickly and sharply, attempting to extend beyond the point is finger bending to, not just to the point where it is bent uncomfortably.
Bend the pinkie out the side, if possible. Fingers can bend much farther back than to the side, making it easier to break a finger by bending it sideways.
Bend the grabbed finger straight back if it is a finger in the middle of the hand and the other fingers are preventing you from properly bending to the side.
Hold the finger down in its broke position for 1 to 2 seconds to increase the pain caused.
Follow up with additional escape strikes, such as a knee to the groin or stamp to the foot, to gain separation and further injure and slow down your attacker.
Escape from the attacker as soon as you have the opportunity to do so, calling for help from any one in the area who can provide it.