The Nasstoys Dynamo Vibrating Masturbator Cup accommodates all penis shapes and sizes with its sleek, discreet design. Open at both ends, the user may insert their penis using a water-based lubricant and stroke as they would naturally with their own hand. 10 powerful vibrating functions and the textured tunnel deliver powerful sensations. This stroker can also be a fantastic oral sex aid to be used with a partner! Place over the penis of a partner using your favorite flavored water-based lubricant then stroke up and down while only placing as much or as little into one's mouth as desired to create a deep-throat like sensation without the sore jaw! Please clean before and after each use with toy cleaner and allow to dry before replacing the caps onto each end. To power on, press and hold the power button until vibration begins then press again to begin cycling through the vibration patterns. Press and hold to power off. To charge, please align the magnetic connectors on the charger to the contact points on the stroker's outer shell then connect the USB end into a power source.