These simple and powerful nipple suckers from Size Matters are perfect for anyone looking for consistent, strong suction. All you have to do is place the base of the suction cup firmly against your body, then turn the easy-to-grip control cap to create instant suction. Enjoy the sensation of light suction or turn the knob further to create a vacuum. Just turn the cap back to return the internal piston to its original position and release the suction.