It houses an accelerometer which causes the motor in the pleasure object to respond to movement in the controller on 180 degree axis.
The controller is ALSO a massager, powered by 1 AAA battery. It can be used to bring additional stimulation (covered in smooth silicone) or can let the partner feel the vibrations the other is experiencing.
Both pleasure object and controller are fully waterproof
8 Stimulation modes, including motion control, offer near endless variety