Vibrating Anal or Vaginal Balls. Inserted into her vagina or anus, or his anus, these ben-wa balls vibrate due to their internal weights. Even the slightest tremble will activate exquisitely silent vibrations that never require batteries. Enjoy non-stop internal vibrations with these luxurious weighted vibrating balls. Experience the rush of smooth stimulation with each gentle tug of the sturdy retrieval cord. The sleek weighted balls are self-pleasurizing and continue to vibrate with each movement of your body.