Shipwrecked: The Island Queen

Book 1 of the Shipwrecked series. A sailor shipwrecked on an Island inhabited only by women, is found and nursed back to health by the queen. She has sex with him as she is soothing his sunburn. She says he will be allowed to have sex with her daughters too but she wants him to have sex with her while her daughters watch and learn about sex. They have sex and the girls soon become his mates too.