The main idea behind it was to "use yin to strengthen yang." In order to improve their health and prolong their lives, men were taught to do their best to bring women to orgasm, so as to absorb the yin (feminine) energy released by women during orgasm.
房中術又名「御女術」，其主要理論為「採陰補陽」，教男人努力使女性達到高潮，以吸取女人高潮時釋放出來的陰氣，達到養生、長壽的功效。