b) Key Points
Capture the arm solidly between your legs to remove any wriggle room and retain this squeezing action on his arm when kneeling down his back (stay off his neck!).
Keep the bent wristlock applied with his fingers pointing at his head as the back of his wrist will be in a known (and, for him, anatomically weak) position for handcuffing.
Make sure that the handcuffs are applied so that the backs of his wrists are facing each other (i.e., apply the cuffs to the backs/tops of the wrists).
Apply the handcuffs in any way you like, but use a well-practised method that will always work on those arrestees with tight shoulders or by officers with big bellies (there may not be room to pass the cuffs between your torso and his arm); under stress you may panic when this lack of passage for the handcuffs becomes apparent.
Use your limiting fingers (index and pinkie fingers) to restrict your fingers to the end portions of the chain as this will keep them away from the sharp rachet teeth and to help secure your grip on the handcuff chain itself.
For those with big hands, let the top part of your hand overlap the other cuff for later readjustment).
PRO TIP: the chain-link lock allows your handcuffing hand to fulfill the two functions of both holding onto the handcuffs while applying a bent wristlock (other handcuffing styles release to bent wrist lock to accomplish handcuffing).
Bend the individual’s handcuffed arm onto his lower back while retaining this cufflink lock and shake his free hand with your free hand (or grab his thumb).
Release the chain and search his rear waistband immediately by exposing his lower back through the lifting of his lower rear upper-body clothing over the handcuff chain.