Previous parts:
One
| Two

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Training Luna was fun.

The pretty 18-year-old was confused and embarrassed about everything, and deeply reluctant to do anything that Jayna told her to – but even more terrified of anyone seeing the video in which she had said she wanted to fuck her father and suck her brother’s cock.

“Don’t worry, sis,” said Jayna. “Just do what I tell you, and everything will be okay.”

“Don’t call me that!” protested Luna. “You’re not really my sister!”

They were sitting together on Luna’s bed, talking in hushed tones so the other members of the family wouldn’t hear them. Jayna thought Luna looked exceptionally pretty, with her face flushed with embarrassment and her golden-brown hair in disarray.

“Sure I am,” said Jayna. “I’m your big sister now. Don’t you want a big sister to look out for you?”

“No! And you’re only a year older than me!” objected Luna.

“Well, then we must be friends,” said Jayna, “or maybe girlfriends.” 

She leaned forward and tried to kiss Luna on the lips, but Luna pulled away.

“Stop,” said Luna. “It’s gross. I’m not into girls.”

Jayna feigned innocence. “Then why did you molest me in your bed? Why did you force me to let you lick my pussy?”

Luna scrunched up her face. “No!” she said. “It was you who did that! I didn’t want to! You’re just some… colossal lesbian slut, and you’ve come into our house and made everything gross.”

“I’m bi, not gay,” said Jayna. “I like boys too. And anyway, I don’t think it’s me who’s the slut. I seem to recall that you said you wanted to fuck your own father and brother.” She raised her voice slightly on this, and watched Luna flinch, and glance at the closed door. 

“Sssh!” hissed Luna.

“Shall we go show them the video?” asked Jayna.

“No!” squeaked Luna.

“Well, I only keep secrets for my girlfriends and my sisters,” said Jayna. “Would you like to be my sister and my girlfriend?”

She looked at Luna, waiting for an answer. 

There was a long silence.

Then, finally, Luna said, “Okay.”

“Okay what?” demanded Jayna.

“I’ll do what you said,” said Luna.

“You want to be my sister and my girlfriend?” asked Jayna. “Say it. Out loud.”

Luna blushed even deeper. “I want to be your sister and your girlfriend,” she whispered.

“Good girl,” smiled Jayna. She leaned in for a kiss again, and this time Luna let it happen. She didn’t kiss back, refusing to open her mouth, but it was a start.

“Now,” continued Jayna. “Undress.”

“What?” asked Luna, surprised.

“From now on, you don’t wear clothes in your bedroom. If your parents are home and awake, you can wear a bra and panties, but if they’re not home or asleep, you have to be naked.” Jayna smiled. “Come on, get started. You want to please your girlfriend, don’t you? And keep that video a secret?”

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The next week was a process of getting Luna comfortable with obeying her new foster sister.

The “no clothes in your bedroom” rule was just the start. It got Luna used to being nude when other people (such as Jayna) were fully dressed, and it got her used to feeling vulnerable and ashamed. In addition, it meant she spoke quietly to Jayna when they were together, and was afraid to raise too much objection to Jayna’s ideas, for fear that her parents or brother would come to see what was going on, and find Luna undressed.

Jayna followed it up by placing a cute pink padlock on Luna’s underwear drawer. Only Jayna had the key, and Luna had to come to Jayna if she wanted to wear panties or a bra. In most situations, Jayna refused to give her any, and Luna soon became used to going without panties around the house. It made her reluctant to spend too long with her parents and brother, for fear they might see her bare ass under her skirt, and even more reluctant to spend time with her school friends, and all of that made her more isolated and more reliant on Jayna for company.

Luna’s frequent protestations that she “wasn’t a lesbian” became irritating to Jayna, so she first of all forbade Luna to ever claim that she wasn’t sexually interested in women, and then began a nightly session of “training”. She would seat Luna (naked) at the computer in her room and make her browse lesbian porn on the internet. Then Jayna would kneel between Luna’s legs, under the desk, and lick and play with her pussy, until Luna inevitably started to become wet and aroused.

Then she would spin Luna’s chair around to face the bed, where Jayna would sit, naked, filming Luna with a phone. She would make Luna rub her pussy, while staring at Jayna’s cunt, while audibly chanting, “I want to fuck my father and brother.”

Luna was always terrified someone would overhear this chant, and it gave her incentive to orgasm as quickly and intensely as possible so she could stop saying it. And so she would cum, while staring at her foster sister’s fuckhole and saying that she wanted to fuck her male relatives. 

And Jayna filmed each one of these sessions, deepening her collection of humiliating footage of her pretty new sister-slave.

And at night, they slept together in bed. Jayna slept normally, with her head on the pillows, but she made Luna sleep upside down, with her face resting against Jayna’s cunt. Jayna would part her legs and make Luna lick her to a pleasant orgasm each night, and then make Luna sleep with Jayna’s cunt-juices on her face and the smell of pussy in her nose.

To help Luna sleep, Jayna had also procured a special pair of “sleep panties” for her sister. These not only looked pretty, in silky pink, but had a pair of short stubby vibrators attached to the inside, which would press against the entrance to Luna’s fuckhole and anus respectively. These operated randomly during the night, switching on and buzzing at her erogenous zones, before turning off again long before she was able to cum. Their primary purpose was to ensure that Luna’s sleep would be shallow, horny, and filled with erotic dreams, and that she would start each day tired, confused, and aroused.

After the second day of this disrupted sleep, Luna complained, and asked why she couldn’t just sleep normally. Jayna smiled, and told her that big sister knew best, and that she would need to be punished for arguing. Her “punishment” was a pair of wireless earbuds that she would also wear to sleep now. These were synced with the vibrators, and whenever the vibrators turned on, Luna would now hear her own voice in her ears, moaning “I want to fuck my father and brother”.

Punishments became increasingly important. When Luna did anything to disagree with Jayna in public, no matter how small, Jayna delighted in grabbing the hem of Luna’s skirt and flipping it up, to show her bare ass and pussy. This always happened where no one would notice – but it always made Luna go bright red, almost as humiliated as if someone had seen, and, more importantly, it would make Luna submissively obedient for at least an hour, until the shame had worn off.

She also liked to remind Luna that she had said she wanted to fuck her father and brother. And sometimes people *did* overhear this.

They were at a mall one day, because Jayna had decided that Luna needed to buy some sexier clothes. Jayna was leading her sister-slave through the mall, when Luna paused. 

“What’s the matter, sis?” asked Jayna.

“Please,” begged Luna in a whisper. “Can we not go up the escalator? People on the lower steps will… see…”

She meant that they would see up her skirt, and be able to view her bare pussy.

“No,” said Jayna. “Go up the escalator.”

But Luna hesitated, so Jayna said, loudly, “I can’t believe you have sexual fantasies about your own father.”

Several shoppers turned to look, and Luna went white with shock.

“Ssh!” she hissed. “Jayna! Ssh!”

“And you rub your pussy while thinking about fucking your brother!” added Jayna, even louder.

Luna looked like she might faint.

“Going to come up the escalator now?” asked Jayna, in a quieter voice.

Luna nodded.

And people on the lower steps ‘did* look up as they ascended, at this girl who apparently fantasised about fucking her family, and they *did* see that she was wearing no panties. 

And Luna learned not to ask questions about where Jayna was taking her, or object to where she was being taken.

Afterwards, before they left the mall, Jayna took her sister to a quiet side passage, only used by the cleaners, and pushed Luna up against the wall.

Luna was still shocked, and looked like she might cry. Jayna kissed her.

“You’re so lucky,” she whispered as she kissed Luna. “You’re lucky to have a sister who hides your secrets.”

Luna made a protesting murmur. 

Jayna reached down, and before Luna could understand what was happening, she had uncinched Luna’s skirt, leaving the girl completely naked from the waist down.

“Sssh,” she said as Luna tried to protest. “Sssh. Don’t draw attention to it. No one will see as long as I’m pressed up against you. And I’ll keep your slutty secret. I won’t tell anyone that you’re half-naked here in public. I won’t tell anyone that you rape me with your tongue every night. I won’t tell anyone that you masturbate while thinking about your father and brother.”

Luna *did* start to cry now, from shock and embarrassment and confusion, and Jayna thought again that her new foster sister was far prettier when she was crying than when she was happy.

She kissed Luna again.

“You’re lucky, aren’t you?” she asked.

Luna made a confused sound.

Jayna reached down between them and cupped Luna’s pussy in her hand. To her pleasure, she discovered that Luna was wet.

“Are you getting turned on from being a slut in public?” she asked. “I can keep that secret too. Tell me you’re lucky to have me as a girlfriend and a sister.”

Luna whimpered, then whispered, “I’m lucky you’re my girlfriend and my sister.”

“Tell me you love me,” said Jayna.

Luna whimpered again.

Jayna squeezed her pussy mound, just hard enough to be a little painful – and then shifted her weight, as if to suggest she might pull away, and leave Luna bare-cunted with no coverage.

“I love you,” gasped Luna.

And Jayna kissed her as a reward. Luna’s mouth tasted salty and lustful and delicious, and as the kiss went on, she heard Luna moan sluttily into her mouth.

“Keep saying it,” she said, after the kiss. And she slipped a finger between Luna’s pussy lips and began to gently stroke her clitoris.

“I love you,” whispered Luna. “I love you. I love you. I love you.”

And by the time Jayna brought Luna to orgasm using her fingers, even Luna didn’t know whether what she was saying was a lie, or the simple, undeniable truth.

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If you enjoyed this story, you’ll love my e-book Sisters – Stories of Sisterly Lust and Sibling Rivalry, available for only $3.99 USD at my creator site! (Click here to view in store.)

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