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.