Your movement controls the motion of the balls: when you`re bouncing up and down, so are they. When you`re rocking back and forth, they`re rolling with your motion. (You can see some obvious applications for this, right? Our favorites include spiced-up spanking and holding a vibrator against the base.) Whether you`re looking to add some anal training to partner sex, make solo play extra special, or just walk around with a little secret, B BALLS DUO are dynamic, discreet, and completely unique.