The Monkey Rocker is a proprietary, self-propelled sex machine that is basically built like a glider rocking chair but instead of a seat and a back it has a gap in the center where a sex toy is placed. The gliding motion moves the toy up and down to facilitate penetration.
According to the product's website, the "Monkey Rocker doesn't have any expectations...will never berate you for taking too long, coming too soon, leaving suddenly, staying out all night, talking too much, drinking too much or seeing other machines."