Source: Wiki
http://en.wikipedia.org/wiki/Ben_Wa_balls
Ben Wa balls, also known as Burmese bells, Benoît balls, Orgasm balls, Venus balls or Geisha balls (Chinese: 阴道球; pinyin: yīndàoqiú “vagina ball", or Chinese: 内用球; pinyin: nèiyòngqiú “internal-use ball"), are small, marble-sized balls, usually hollow and containing a small weight, that roll around and are used for sexual stimulation (by insertion into the vagina). Available in a variety of forms, the balls may be solid, or contain clappers or chimes within. Other, larger versions made of plastic encasing lesser balls are called Duotone balls. They are used by inserting them into the vagina and using muscles to hold them in, stimulating movement and vibration.
Ben Wa Balls have a varied history; their origin and method of construction varies depending upon location. Most information concerning Ben-Wa Balls is vague and probably apocryphal. Originally they were made of a single ball placed in the vagina, used to enhance the act of coitus, but then evolved into multiple metal covered balls linked by either a chain or silk string for easy removal. Usage of Ben Wa balls creates a subtle stimulation, not meant to bring the user to immediate orgasm but rather to tease. It is possible to leave Ben Wa balls in one’s vagina all day, or use them while seated in a rocking chair,[1] for an effect that some find pleasurable. At the end of the sixteenth century, Ralph Fitch, an English traveller, encountered them in the Shan States of Myanmar.[citation needed] He described their use there by men. Less than a dozen years later, the Florentine merchant Francesco Carletti also reported their use in Thailand, where they were used to enlarge the penis.[citation needed]
Ben Wa balls may also be used to simply increase the strength of the pelvic floor muscles, much as Taoist sexual practices has been used for centuries,[citation needed] and the Kegel exercises are used today. Similar to Kegel exercises, Ben Wa balls and other shaped vaginal weights are recommended by gynecologists and obstetricians to increase vaginal elasticity and bladder control. Vaginal weights come in a spherical shape and are used in increasing weights to strengthen the vagina, which improves sexual performance. Mild urinary incontinence, such as that which occurs while coughing, laughing, or sneezing and occurs more often as women grow older, can be treated with Ben Wa balls,[citation needed] vaginal weights, or Kegel exercise.
Practitioners of such spiritual traditions as Tantra and Chinese Taoism believe that Ben Wa Balls are helpful tools to exercise control and to explore the sensual side of an individual.