Even midget wrestlers are taught and soon know to not reach back behind themselves at an opponent behind them. I see, however, some traditional fighting arts promoting blindly reaching back over their shoulders. Such actions increase risk and offer extremities including your fingers as well as can assist with your balance destruction.

Your humerus bone of the upper arm bends at the shoulder and elbow and in between is a lever that if seized and manipulated can be used to destroy your balance and decentralise you. 

Simply never reach behind yourself and always turn to face combined with hard cover guarding, if required, so that you can identify the threat specifics and targets available for destruction. You do not need to fully turn belly to belly as you may not be able to if being gut wrenched in a powerful bear hug.

Simply by using the most trusty CQC footwork of pivoting and adjusting your footing, you will be able to get a visual on the threat specifics and available targets. Combine your pivoting and footing adjustments with bending at the hips and pushing back and down with your buttocks and you are making your foe wear your weight.

Stamp kicks, reverse pouch squeezing of the genitals, hand edge and elbow strikes, knee presses to interfere with your foes stability all add to the effect and set up of your means of objective achievement. 

The turning action for specific skills executions and in favorable situations can be continued a full 180 degrees.