I did my best with this. I hope those of you who read it enjoy it.
**
Steffany was thrashing uncontrollably on the bed. The sheets were a soggy mess, and her dark hair clung to her wetly. Her older half-sister Dominica was fisting her and teasing her clit with a vibrator. Steff was the more adventurous sister by a wide margin, but as their freshman year came to a close, she hadn't experienced anything to equal Domino's tiny little hand buried in her tight pussy.
"Fuck, Sugarbear, I can't take much more. Please. Make me cum..." she wailed like a tormented soul.
Dominica slowly removed her fist from her sister's pussy as she licked Steff's pussy furiously. Steff stiffened and spasmed as she came, and then gleefully pulled her sister on top of her. The girls kissed as Steffany recovered from her sister's frenzied fisting.
"Sissy, I want to talk to you about something," Domino said between their tender kisses. "I'd like to revisit our arrangement."
The girls had agreed at the beginning of the year that Steffany would consider an exclusive relationship with her half-sister only after Domino had gone on dates with five different people. Domino had dated two guys and a girl but hadn't found the spark that she shared with Steffy.
"I gave it an honest effort, Sissy," she said, "But you're the only one I want to fuck. Well, except Daddy."
"Oh, Sugarbear." Steffany sighed. Her first year at college had been a whirlwind of sex, but as she looked into her sister's incredible blue eyes, she realized that no one pleased her nearly as much as her sister. "You win," she breathed into her sister's mouth as they continued kissing.
Gleeful that she'd finally worn her sister down, Domino started to reach for her sister's pussy again.
"Oh, no you don't, Sugarbear," Steff said as she caught her sister's hand. "We've got a long drive home tomorrow, and we need some rest. I'm so excited to see our baby sisters for the first time."
"Me too," Dominica replied. She continued shyly, "Sissy? Will you help me seduce Daddy?"
"I don't think we can, Sugarbear. We've been over this. I don't think Dad has ever noticed anyone but our moms. You're going to have to clear this with them."
Disappointed, Domino agreed.
The next morning, they'd packed their convertible and said good-bye to their friends for the summer and started home.
Several hours away, their parents were eagerly awaiting their arrival. Steve, Marlene, and Tiffany had all missed their eldest daughters, and their home just hadn't been the same without Steffany's tearabout energy and Dominica's quiet intelligence.
"I can't wait to see Steff and Sugarbear," Steve said. Marlene and Tiffany quickly agreed.
"I'm just glad Steff bore down and kept her grades up. I guess Domino was a good influence. I'm so proud of both of them," Marlene said.
Hearing Daniella and Michelle's cries through the baby monitor, Steve said, "I got it. My turn."
Marlene and Tiffany smiled at yet another reminder of how well they'd chosen the father of their children. He wasn't hen-pecked, he just genuinely loved them and their children.
"So," Tiffany asked Marlene, "How much of Steff do you think has rubbed off on Domino? I'm not sure we can handle two tornadoes."
The women both laughed, and Marlene said, "I don't know. I'm sure it's nothing. But Steff texted me that there was something Domino wanted to talk to us about."
"Oh?" Tiff's eyebrows raised, "Any details?"
Marlene shook her head, "She wouldn't say. I'm not too worried. With Domino's grades, she's not getting kicked out of school, so how bad can it be?"
By mid-afternoon, the girls had pulled into the driveway. Their parents and younger sisters Bethany, Juliana and Gina, rushed out to greet them, and they all exchanged excited hugs.
"Can we see the babies?" Dominica and Steffany exclaimed.
"Of course. Daniella and Michelle are sleeping, but you can peek in on them," Marlene and Tiffany replied.
"Race ya," Dominica said to Steffany and took off at a sprint.
"Wow," Tiff said. "When they left for school, Steff would have been the one issuing that challenge. Maybe we should be worried after all."
"Huh?" Steve said.
"Nothing," Marlene and Tiffany said a little too quickly.
After they'd seen the babies, Steffany and Dominica approached their father. "Daddy? Could you move Steffy's furniture into my room?"
Steve laughed, "I remember when you two fought like cats and dogs to have a room of your own. What's changed?"
"Well, we've just gotten so used to being together all the time, being in the same room will help us sleep."
Steve had yet to say no to either his wives or his daughters, so he set to work moving stuff around.
The whole family spent a quiet evening together with pizza and games, and the girls regaling their younger sisters with amusing stories.
The next morning, the family gathered for a late breakfast, and Steve asked, "Who's up for a superhero movie matinee?" The three younger sisters all started clamoring they wanted to go. Domino began to raise her hand, too. But Steffy stopped her with a nearly imperceptible shake of her head.
"Ok, well, I guess it's just the little ones and me," Steve said, perplexed. Sugarbear had inherited his love of superhero movies, and he was surprised she wasn't eager to go.
"I'm just tired from the drive yesterday, Daddy. I'll go next time," Domino said and pecked her father on the cheek.
Steve piled the three younger girls into the family SUV and headed off to the movies. It was a beautiful day, so Marlene and Tiffany threw on bikinis and indulged in their love of sunbathing by the pool. The older women were just as attractive as their daughters. Dominica and Steffany joined them, but after a little while, Steffany said, "I'm going to go in to make us some lemonade, why don't you help me, Sugarbear?"
Domino was surprised because Steffany was the most self-sufficient of the bunch, so she agreed and followed her sister, curious to see what was up.
When they got into the kitchen, Steff whirled on her sister and kissed her. "I was aching for you last night, Sugarbear. But with the whole family here, I was afraid to make a move. Let's go for a quickie while moms are outside."
Thrilled at her sister's suggestion, Domino grabbed her younger sister's hand and dragged her to the bedroom. They tore each other's clothes off, and Steffany began to make love to her sister with the purloined strap-on their moms had made which they had ordered custom-molded from their father's dick.
"Do you like it when I fuck you with daddy's dick?" Steffany teased her sister as she slammed in and out.
"God, yes, Sissy. Fuck me harder," Domino cried.
Steffany savagely and relentlessly fucked her sister until Domino's eyes crossed with a mind-shattering orgasm.
"Ok, my turn," Domino said, as she got some lube and the vibrator. She lubed up her hand, and then flicked the vibrator on, teasing her younger sister's clit as she slowly, gently and methodically worked her fingers into her sister's pussy until once again she had her whole fist inside her.
"Oh, fuck," Steffany cried, "This never gets fucking old. Do it, Sugarbear."
Domino began to slide her fist in and out of her sister's pussy, and Steffany began to thrash as her orgasm was upon her.
"Just what is going on here?" Marlene said.
Domino and Steffany stopped dead in their tracks, seeing their moms watching their tryst.
"Mom, I can explain..." Dominica started.
"Oh?" Marlene sarcastically asked. "You can explain having half your arm up your sister's pussy?"
"Well, Mom," Steffany interrupted. "If you ever get the chance, I'd recommend it. Sugarbear throws a mean fist. I've never felt anything like it."
"I'd imagine from the sounds you were making," Marlene and Tiffany said in unison.
"Girls, I think we need to clear the air," Tiffany said, and the two women sat on the edge of the bed by their naked daughters.
"What's gotten into you, Domino?" Tiffany asked her daughter.
"Mom, I... I don't know. Having sex with Steffany has changed me. I was a virgin when we left for school, but once we started, we couldn't stop. Please don't be mad. We love each other."
Marlene and Tiffany eyed each other and said to the girls that they could never be mad at them for this. "It would be hypocritical of us," they said.