Ben Wa balls are two connected balls which a girl can insert into the vagina. It’s a sex toy for women.
They are the size of a big marble. Sometimes they are empty, but they can also contain small balls, increasing the amount of vibration when they click against each other.
A girl can wear them while going through her daily routines, the balls rolling around while she walks and moves around. But they can also be used during masturbation or sex with a lover.
Some girls get excited when their vagina is stimulated by the Ben Wa balls, while others are not impressed at all. For them it’s no more fun than using a tampon.

Buying and using Ben Wa balls

See also: anal beads