Heavenly Bodies - Heavenly Bodies, #4

After an asteroid collides with his spaceship, killing all others on board, astronaut Frank Rimmer cryogenically freezes himself to await rescue. When Frank wakes up, he's greeted by a pair of rescuers resembling pin-up girls from his crewmate's calendar. The girls who rescue him are aliens who can project images into Frank's mind and appear as he would like to see them. Sister-clones Mahla and Shahla tell him they sincerely want to learn more about human beings and their mating rituals.
They study "unofficial files" onboard and ask Frank for his help in understanding human sexuality. Can Frank help these two gorgeous angels experience an erotic cultural awakening?