Board Thread:Off Topic/@comment-29684190-20191110024409/@comment-27144409-20200110024911

You misunderstand, the idea is that they bend the elbow, then slide the blade/s through the mechanism over the joint, the way some run the flat of the blade, or a blunt edge, over that general area to wipe off the blood. Also, the  blades might possibly be part of the arms, for easy upkeep and posturing.

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Try running the outside edge oh a forearm through your elbow joint.