Lü Dongbin
Feijianji, another novel from the Ming Dynasty had a slightly different version of this legend. According to Feijianji, Bai Mudan was a common girl (not a courtesan) who was seduced by Lü Dongbin. Later she became very weak since Lu practiced "cai yin bu yang" on her. Meaning he absorbed her yin (female) essence, without losing his own yang (male) essence. When her mother consulted with Buddhist Monk Huanglong (Yellow Dragon), he taught her how to make Lü Dongbin ejaculate and thus restore her yin essence. This event enraged Lü Dongbin, he tried to decapitate Huanglong using his flying sword but failed. In the end Lu admitted his mistakes and acknowledged Huanglong as his teacher.