Ecstasy Bound — Ruth D. Kerce

Book 4 in the Xylon Warriors series. Sex and survival. Xylon Warrior Brianna Koll is determined to concentrate on her duty. But she's drawn to an Earth man, Lieutenant Colonel Sam Briggs, in ways she's never felt before. Now her duty will bring them even closer. She needs to sexually Initiate Sam in order to save Earth. The rite-a breeding preparation and protection ceremony for Xylon Warriors-will alter his semen, so a serum can be developed to protect Earthlings from the Egesa Slave Masters' diseases and poisons. To save Earth, Sam is more than willing to go through the public, erotic, multi-partner ceremony. And to be with Brianna. Her alien genetics intrigue him. But it's become more than just physical. His sexual fantasies about her have grown into true passion. Only their commitment to their people and to each other will enable them to survive and they don't have much time. The Egesa are on their way to Earth to enslave the planet.