The Bacchi. The Lost King, #4

The Bacchi Lefi Dhrahn lives a life of luxury and decadence, but is tortured by memories of a lost love. He survives the pain by surrounding himself with sex, beauty and all forms of self-indulgence. When he meets the alluring Inspector Afton Teris, Lefi believes the detective will make a very nice addition to his string of conquests. He doesn't count on falling in love. Afton Teris is a Valoran, and like all members of his species, is stern, cerebral and disapproves of the frivolous prostitute.
Afton orients as a male, but the beautiful Lefi Dhrahn stirs him sexually, making him question everything he knows about himself. To further confuse his emotions, Afton finds himself tempted by the forbidden pleasures surrounding the Bacchi. When a kidnapping ring strikes close to home, the two go undercover on a brothel barge to investigate a slavery operation. There, Lefi is confronted by painful memories from his past, while Afton is faced with a horror that threatens his future, and perhaps his very life.
Their survival lies with one another, but only if Lefi can set aside his pain and listen to his heart. This title stars a green-haired courtesan that might even tempt Kirk, and a cerebral detective from a species known for gender fluidity.