on a far off alien planet with binary suns that is sparsely populated by humans, Twin girls are on a long and lonely scientific mission. Dirigible filled with instruments that floats over a water planet, studying marine life.  They had experimented sexually with each other while younger and the mission, some people gossiped, was just so the two could be alone together. Describe how incest was not very taboo on the planet because it was so sparsely populated but not common. The two were inseparable when young  but hadn’t fooled around in several years and went to different colleges.  During the mission one sister, Ayala, likes to sunbathe naked, the other, Gwin, is more submissive and reserved, even in the middle of nowhere.  Describe how in the time since the two had experimented, Ayala hadn’t suffered a lack of lovers, both male and female; but on the trip, alone with her sister, she gets horny. She looks at her sister, who looks like her, tall and athletic and nicely tanned, and sees her nipples hard against her tank top. No bra. It’s hot and sunny so neither of them wear much. Ayala being the brash and outgoing one wears even less. She remembers going down on her sister when they were younger.  Insert descriptive paragraph: Since fooling around with her twin, Gwin had only taken one lover, a soft and effeminate man named Bron who nonetheless had made passionate love to her and she remembered him fondly. She also remembered the times her sister had made her cum, indeed given her her first orgasm.  “Cant you do that in your cabin?” She asks, seeing her sister naked on the deck of the dirigible, touching herself while sunbathing.  “The suns are so nice, they made me horny.” Insert dialogue. Ayala asks her to join. Their bodies are the same after all. Gwin demures.  As the trip goes on and the rigid airship floats lazily above the water planet the two sisters do their experiments on the sentient sea plants below. They occasionally get on each other’s nerves in the cramped cabins (insert example) but they also have fun and the sexual tension increases too. Describe outfits: Ayala always seems to be naked or just in panties, her small perky breasts on display. Give example: Gwin gets flustered seeing her in various states of undress. Bending over and displaying her vulva or hairless ass.  They have some wine during dinner one night, get a little tipsy, and Ayala tells Gwin how she loves sucking cock. “I bet you’ve never even done that, sis.” Gwin blushes but is turned on thinking of her sister completely in control over a man’s pleasure. “Sucking cock actually gives you some pointers when it comes to eating pussy.” Gwin gets redder. “Yes I’ve heard stories of your skills, sister.” “You should let me practice.” Gwin declines but that night she masturbates in her cabin. She thinks of Bron fucking her but the fantasy transforms into her sister railing her with a strap on. Ayala can hear her moan through the walls. She smirks and devises a plan to seduce her sister.