[Varyon]

You could probably use the same mechanics for turning the enemy around (thus denying him defenses) and not turn him around, but rather say you've bound him enough that he can't defend. The foe can then use the same mechanics as to turn back around, except fluff-wise this would be him struggling to regain some degree of movement (thus being able to defend again), rather than just turning back around. The mechanical difference is only in edge cases (enemy has 360-degree vision, or his attackers are in a circle such that he should always get a defense against some of them), so you could easily just consider this as a special effect (some RAW special effects - like disintegration from a fatal Heart Attack Affliction, or decapitation from a fatal cutting attack to the Neck - have similar edge-case caveats).