Ball binding
From wipipedia.org
Ball binding is the act of tying up the scrotum of a male (and often penis too), usually with rope ("balls" being a slang term for testicles). It is often an addition to bondage, and is sometimes done for humiliation. If the ropes are tight and painful, it can be regarded as genitorture; care must be taken not to cut off the blood supply for a long period, or the genitals can be permanently damaged.
If the ball binding is not attached to other ropes, it does not in itself contribute to the bondage. However, it may be attached to a crotch rope joined also to wrist bonds as a way to restrain the arms.
