An automated erotic stimulation device is a mechanical device used to simulate human coitus. It is a more sophisticated version of the much simpler vibrator. The device can be used by either sex to excite the anus or vagina. A typical machine works by the transfer of rotational force from a motor to a directional motion on a shaft, which is tipped by a dildo. These devices may be associated with, but are not limited to, BDSM play. Another design consists of a dildo attached to the end of a rotating device such as an electric drill, which rotates to produce stimulation.