Ben Wa balls

Ben Wa balls, also known as orgasm balls, rin-no-tama,^: 166 Venus balls, or mien-ling, are marble-sized balls, usually hollow and containing a small weight, that may be inserted into a vagina, and held in place by the pubococcygeus muscles. They may be used as a sex toy by creating sexual stimulation or pleasure by rolling around in the vagina stimulating movement and/or vibration. They create a subtle stimulation that does not bring the user to immediate orgasm, but rather teases.

They may also be used for a medical purpose, such as to increase the strength of the pelvic floor muscles, much as Taoist sexual practices have been used for centuries and the Kegel exercises are used today. Similar to Kegel exercises, Ben Wa balls and other shaped vaginal weightlifting equipment are recommended by gynecologists and obstetricians to increase vaginal elasticity and bladder control.

It is possible to leave the balls in place in the vagina all day, or use them while seated in a rocking chair. Health experts caution against prolonged placement of foreign objects in the vagina due to the risk of infection.