Carrageenan, which is named for its principal ingredient, a gel-like substance extracted from seaweed.
Carrageenan is used as a thickener in everything from ice cream to shampoo to shoe polish, but according to Kehoe its lubricating properties may be its biggest advantage. In addition to being naturally viscous and slippery, carrageenan is thixotropic. That means it thins under pressure and regains its viscosity when the pressure is released.
"It pumps easily and then stays where you put it," Kehoe said.
He got the idea for it based on the experience of his wife, who after menopause found sex uncomfortable.