An apparatus has a bottom sphere and a top sphere connected to the bottom sphere to define an interior volume with a central plane. The top sphere includes a concave surface at an angle to the central plane. A motor is positioned within the interior volume. A processor is positioned within the interior volume and is connected to the motor. A memory is positioned within the interior volume and is connected to the processor. The memory stores instructions executed by the processor. The instructions include hand stimulation sessions. Each hand stimulation session comprises a sequence of cycles, where each cycle is a sequence of vibration intensity values applied to the motor.