Use Your Sisters Instead

"Michael is this true?"

Mary heard footsteps echoing down the hallway.

"No way," Chastity said. She stood behind her mother, staring in wonder at her brother and sister on the bed.

"I'm sorry, Mom," Michael said, "I was in my room and feeling, you know. I was going to start rubbing but I know that's wrong. And then I thought, well, doesn't this solve the problem completely?"

"Well..." Mary said, starting to feel herself pulled towards saying yes. I mean, I guess I should be proud of the boy in some way.

"M... Mom?" Hope asked.

"He's not hurting you now is he?" Mary asked.

"Oh GOD no," Hope said, "Though he is... uhn... neglecting his lubrication duties."

"Sorry, sis," Michael said. He let go of her hips and started massaging her breasts.

"Oh, that feels great, Michael," Hope said, "But I'd like it if you touched a little lower, too."

Michael obliged. He took one hand and started rubbing between his sister's legs. She moaned appreciatively.

"Well as long as you're not hurting her I guess it can continue, for now," Mary said, "Just don't do it every time."

Given permission, Michael and Hope seemed to speed up. Their movements became more frantic. The sounds of their sex grew louder and less restrained. Instead of just lying back, Hope moved her butt up and down to match her brother's rhythm. Her sex hungrily stretched around his cock.

"But Mom," Chastity said, "It's not fair that Hope gets to fuck Michael and we don't."

"Yes," Tabitha said, "It seems like something we should each get to experience."

"I don't know..."

"It's OK," Hope said, her body bouncing, "OH! So good! Michael c... clearly knows how to treat his ssssssiiiiiiisters."

"Fine. It's agreed," Mary said, "Now let's give them some privacy." She herded the two girls into the hallway and carefully closed the door behind her.

As she walked down the hall, she heard the telltale sounds of the siblings' shared crescendo.

*

Mary had to run errands that afternoon, but she came home to quite a sight. Chastity was bent over the couch, completely naked. Blonde hair ran like waterfalls onto the cushions. Her prominent posterior hung over the armrest, lewdly displaying her vagina. Chastity had bragged to Hope before that her clitoris was easy to find and Mary saw that her daughter wasn't kidding. Chastity's little man in the canoe was more like a giant in his yacht.

Michael stood behind his sister, just as naked. He had his hands on her hips and was lining his cock up like he was about to penetrate her.

"Oh, hey Mom," Hope said. She was sitting on the couch by Chastity's head, lightly stroking her sister's golden hair. Hope was fully clothed, but Mary could see that telltale flush running up her daughter's neck. "We're just doing our sibling duties."

"Um, I can see that," Mary said. She almost dropped her groceries to the floor. "But do you think, maybe, it might be better to, you know, do this someplace more private?"

"It was way easier to fit everyone out here," Tabitha said. She was standing by her brother's side, also still completely dressed. She had on her glasses and seemed to be studying the entire act like it was a new science project. Mary practically expected her youngest daughter to have a notebook and a pen.

Mary wanted to complain, something about this seemed particularly unwholesome. She couldn't say where it crossed the line exactly. The public aspect of it, perhaps. But then she'd already given them permission for that. The way all three girls were getting along, helping their brother, Mary was almost proud. From a certain point of view.

"Can we get on with this?" Chastity asked, "This isn't exactly comfortable you know."

"Quit complaining and take your brother's dick like a good little sister slut," Hope said, giving Chastity a light slap on her cheek.

"Hope!" Mary said, "I won't let you speak to your sister that way."

"Oh, I don't mind, Mom," Chastity said, "It's part of my ummm, lubrication process."

Mary looked over and, sure enough, her daughter's vagina certainly seemed ready to take a penis. The lips were dark and hanging open. A thin line of girl drool dripped down to the carpet.

"Girls, I'm sorry," Mary said, "Something about this seems off."

"Well, why don't you stay and supervise Mom?" Michael asked.

"That would be great Momma," Tabitha said, "That way you can correct us if we do anything wrong."

Oh Lord, preserve me. "Well, OK. I guess."

"Excellent," Michael said, "Tabby Cat, will you go ahead and do the honors?"

Tabitha gave a little curtsey and stepped forward. She took her brother's cock in her hand and hung the head in Chastity's opening. She did it daintily, like hanging a dress that she wanted to keep wrinkle-free for a fancy evening.

Chastity made a little grunt as Michael started pushing forward. From this position, Mary could easily see Chastity's vagina stretching to accommodate her brother's thick, purple pole. Michael sighed, content, as his testicles bounced against his sister. Fully buried between her legs.

"God that's nice," Chastity said, her voice muffled by the pillows. "You may be an idiot, bro, but you have the best cock."

Michael slapped his sister's ass. "Damn straight. About the cock part, I mean. Not the stupid thing."

"Seriously," Chastity asked, her voice muffled by the cushions, "You're making my point for me."

They moved in silence for a while, creaking against the couch. Michael ran his hands down his sister's flanks. Tabitha watched them both, intently. Sometimes bending down to get a different angle. It really felt like some sort of strange demonstration. Human Reproduction 101.

Michael moved almost gracefully in his sister. He was clearly trying to be gentle.

"Jeez, are you trying to tickle me or what?" Chastity asked.

"Language, dear," Mary said.

"Well then tell Michael to quit messing around and fuck me," Chastity said, all pretense of propriety gone. "I can barely feel what he's doing right now."

"This is how Hope liked it," Michael said.

"Well save it for when you're with her, then. I'm a real woman and this pussy needs pounding."

"Every woman is different, Michael," Mary said, "You need to respect what Chastity is doing for you, by understanding her unique needs."

"Oh OK," Michael said. He started to pump Chastity faster. His thighs slapped against his sister's ass. Squelching sounds filled the room. Mary could smell Chastity's unique, feminine scent. There was something sort of beautiful about this, in a way.

Chastity reached back like she was about to rub herself, then stopped. Hope noticed her sister's dilemma. "Michael don't neglect your sister."

"I can't reach under her in this position," Michael said.

"I told you this was stupid," Chastity said.

"Shut up, slut," Michael said and slapped Chastity's ass so hard it left a hand mark on the cheek, "Take it like a good sister."

Mary gasped but Tabitha held her back.

"Part of her...?" Mary asked.

"Yep," Tabitha said, then shrugged. "I don't get it, but then, Chastity doesn't wet herself every time she orgasms, either. Like you said, everyone's different."

Michael was really plowing his sister now. Chastity's face pushed uncomfortably into the cushions. Rather than using his sister's hips to steer her, Michael was now holding on to them like handrails. As if he might collapse without them. His breathing coming in great gulps.

"Is he getting close?" Chastity asked, "I'm getting close."

"Well, Michael? Are you?" Hope asked.

"Uh huh."

"Well, OK then. Answer your slut-sis when she asks you something," Hope said.

Michael reached his hand forward and found his big sister's large breast. "Holy fuck I love your big boobs," Michael said.

"That's why she's our Chas-titty," Tabitha said, giggling. Michael, spurred on by holding his sister's breast, began frantically driving in and out of his sister.

"Ohhhhhh YES!" Chastity cried, "Harder, dammit! No, not my tit, dummy. My pussy. Goddammit, give it to me."

"Ahhhh... Getting close," Michael said.

"About fucking time," Chastity said, "I've been waiting forever to burst. Now fill me up. Give it to me good. Give to meeeeeee!"

Michael gasped, then roared. "I... I'm doing it, sis. I'm stuffing you full!"

Chastity was clearly cumming with her brother. Her mouth open in a silent O. Her head tilted to the sky. They both seemed locked in that moment, frozen in their ecstasy. Then it cracked and they both fell back. Michael bent on the ground. His sperm dripped down his sister's leg.

"Oh!" Tabitha said, "I'll get that." She reached with a tissue and scooped up Michael's spend. Michael stayed curled on the ground. Chastity stood up on shaky legs. Hope helped hold her up, and the two of them slowly made their way back to the bathroom.

Mary looked at what her life had become and sighed. Well, she thought, at least that ought to hold them for a while.

*

After dinner, Mary got caught up in a show and stayed up far too late. She snuck upstairs, but saw a light escaping under the door to Michael's bedroom. Mary knocked - she hoped her son wasn't up late, troubled with something.

She needn't have bothered. Instead, she found Michael laying back on the bed. Hope firmly planted on her brother's cock. Her body hung over him. He was holding her tiny breasts in his hands while she slowly rode up and down on his member. Chastity was sitting next to them on the bed, naked as well. Watching intently.

"Lord, don't you ever stop?" Mary asked, "It's two in the morning!"

"Shhhhh, Mom," Chastity said, "You'll wake Tabitha."

If their mother's presence bothered them, the siblings didn't let it show. Hope continued to ride her brother, moving almost sensuously - snake-like, Mary thought. Michael's head rested against the pillows, eyes slammed shut.

"Michael couldn't sleep," Chastity said, "And my pussy. I mean my vagi..."

"It's fine," Mary said, "Pussy is fine."

"Right," Chastity said, as if adding it to her ledger, "Well it was really sore from earlier today. So Michael agreed to suffer with second-best."

"Shut up!" Hope said, trying to slap at her sister, but she missed. Mary noticed it didn't slow Hope's humping one bit.

"You're saying that I shouldn't put down Tabitha so easily?" Chastity asked.

"You're not... second best, Hope" Michael said. "You're practically perfect."

"Oh, I know, baby," Hope said. She rubbed Michael's head affectionately.

"I don't know, bro. Hope is nice and all, but don't you wish those tits were a bit more of a handful? And that little clit. I'm surprised you can even find it most times."

"Oh, he can find it all right," Hope said, then she shuddered as her brother did just that.

The three of them all kept going, as if they'd forgotten Mary was in the room. She cleared her throat and finally the siblings froze.

"It's just all these positions," Mary said, "What's wrong with lying back and letting your brother give you his cum?"

"Michael was really tired, Mom," Hope said, "I told him he needed release before he could sleep, but he wouldn't do it unless I helped him. You know Michael. He can be very stubborn."

Mary stood there, in a bit of shock. The siblings took her silence as permission and Hope, once again, began riding her brother. She leaned forward, letting her tiny breasts drag over her brother's chest and the two started to move more erratically. Urgently.

"Going to cum!" Michael cried. His sister straightened like she'd been shot. Her whole body trembled and her chest turned red. Then she fell forward and rested her head on Michael's shoulder. She reached up and petted her brother, lovingly.

"Thanks for my midnight treat," she said, then kissed him on the forehead. It all felt very matronly, to Mary. Sweet in a strange sort of way.

Hope carefully climbed off her brother. A splatter of sperm dripped out of her and onto Michael's chest, but he didn't notice. He was already dead asleep.

"I still say he'd have been happier cumming in me," Chastity said.

"Chastity stop teasing your sister," Mary said

Hope shushed them both. "Please be quieter. It took forever to get him down."

"Fine, we'll talk more about this in the morning," Mary said. The two girls nodded sullenly, then all three of them tip-toed out into the hallway.

*

The next morning, while Michael slept soundly in his room, the rest of his family ate breakfast together in the kitchen. Mary was glad to get some time alone with her daughters. Her plan had been working so well, but now it seemed to be spiraling out of control. Yes, Michael was almost certainly not masturbating. It was probable that he wasn't even touching himself, which was amazing - a goal she could never have even have hoped for.

But this craziness with the 'lubrication process' and doing each other all over the house. And did they really all need to be together every time?

"We thought you'd be happy," Tabitha said, "We're supporting each other."

"And it's not always all of us," Hope said, "Tabitha wasn't there last night."

"I'm still sad I missed it," Tabitha said.

"It was nothing," Hope said.

"You can say that again," Chastity said.

"Shut up, Chas-titty," Hope said, taking a playful swipe at the middle sister. Then she turned to Tabitha "Michael was cranky before bedtime."

"God, why does he always fight sleep when he so clearly needs it?" Tabitha asked.

"Please let me talk," Mary said, "I'm glad that you're all working together to help your brother, I really am. I just wish you could be more wholesome about it."

"We don't want to upset you," Hope said, "But we also think we should be able to decide what's best for us."

"You're always welcome to come watch, Momma," Tabitha said, "To help, like, answer questions and stuff. We want you to be a part of this."

"Watch?" Mary asked. That sounded uncomfortably close to something inappropriate in and of itself.

"Look Mom," Chastity said, leaning forward and looking as serious as she'd ever seen her blonde daughter, "You pushed us into this and we agreed. Now it isn't enough unless we do it your way? No. You made it our job and so you have to respect how we go about it. Unless you want us all to stop entirely?"

Mary thought about calling Chastity's bluff. But she decided it wasn't worth it. Like they said, she was getting what she wanted. Did it really matter all that much if it wasn't happening exactly as she'd hoped?

"Of course," Mary said, "You should do what you think is best."

"Thanks Mom," Hope said. They all shared a hug. Then Tabitha went upstairs to wake Michael for his morning 'exercise.'

*

When Mary came home that night, she again found all her children on the couch. It seemed this was their new favorite spot, like a flock of geese landing in the middle of some random corporate park every spring.

All four siblings were naked. Michael was on his back on the floor and Tabitha was on top of him, like Hope had been before. Except Tabitha was facing towards Michael's feet. She was bouncing up and down, sort of distractedly.

Chastity sat by Michael's head. Her massive breast hung over his mouth. It looked a bit shiny, as if it was covered with his saliva. Chastity had a bit of a sour look on her face when Mary caught her eye. The blonde made a deep sigh and shifted slightly, as if uncomfortable.

Hope knelt at Michael's feet, facing Tabitha. She held each of her baby sister's hands and she was speaking low, encouraging her.

"That's good, Tabby Cat, keeping going up and down like that. Try to lean forward a bit more. Like I showed you," Hope said. She looked up, "Oh, hey, Mom!"

Tabitha did her best to turn around while still sitting on Michael's cock. "Hi Momma," she said, "I'm so glad you're here. Hope is assisting me with Michael."

"I can see that, dear," Mary said. She did her best to keep her expression neutral. She'd agreed to... well, whatever this was. All that time she'd wanted to shed her responsibility, but now that the kids had taken control she felt forgotten. Left out. "Don't let me stop you," she said, wistfully.

"OK good," Hope said, then told Tabitha, "Now try doing it on your own. How's that?"

"Reaaaaallllly good," Tabitha said, "There's like this... spot in there. His head keeps rubbing against it every time I move and it's like... FUCK. Lightning in my pussy."

"That's your g-spot," Chastity said. She kept looking at Michael and then back at Mary. As if contemplating something.

"It's, like, the other side of your clitoris," Hope said.

"God, I can only imagine what it would be like to stimulate both at the same time," Tabitha said, "Too bad Michael can't get it from there."

"Oh, I can do that for you," Hope said. She let go of one of Hope's hands and reached for her younger sister's sex. Mary stifled a gasp. This was clearly them testing her. They didn't actually want to do these things. They were pushing boundaries. Making sure she'd keep to her bargain. That was all.

Tabitha moaned as Hope made contact. She started moving up and down faster, like rubbing herself between the rock and a hard place of her brother's cock and her sister's fingers. She reached over to Hope and started returning the favor. The tall brunette sighed as her youngest sister touched her precious center.

"Fuck it," Chastity said. Facing his feet, she straddled her brother. Chastity then wrapped her arms around Tabitha. Rubbed her youngest sister's breasts from behind as she slowly lowered her sex onto his mouth.

Mary waited for Michael to say something. Instead, he tilted his head up and started to lap at his sister's eager quim. "Fffffffffffuuuuuuck," Chastity said, "Finally found a use for that big mouth of yours."

"Mmmhmm," was all he could say.

They had become like one huge monster, the four of them. A creature made of writhing arms and legs. Heads buried against each other. Only capable of moans and whimpers. Slowly sliding across the living room floor. Crawling towards forbidden euphoria.

Tabitha increased her pace on her brother's cock. Her movements got more desperate. Driven. Her sisters manipulated her from both sides. Hope shook as Tabitha rubbed her. Chastity trembled on her brother's tongue. And then suddenly the four siblings started to tremble as a massive shared orgasm rolled through them.

It started with Hope. She made a noise like she'd burned her hand on the stove. A loud "hssssss AH!" Her chest and face flushed. Hope's orgasm dominoed into Tabitha's. "Oh FUCK!" she bayed up at the ceiling. A burst of clear liquid shot out from her sex and spattered her sister's bare breasts. Michael grunted under Chastity, who suddenly bent back, mouth hanging open. A chorus of ecstatic cries and elated sobs. Gradually they slowed and carefully leaned back against each other.

Tabitha looked down at Hope, covered in her sister's girl cum. "Oh God, Hope, I'm so sorry," she said, sounding near tears.

"Oh, it's fine, baby. It's beautiful," Hope said and hugged her sister tight.

"You manage to fill our sister up, Michael?" Chastity asked.

"I sure hope so," Tabitha said, "It's already leaking out of me. There's too much for my little pussy."

"That's all I've got," Michael said.

"Better not be," Chastity said, "My pussy is expecting her own delivery before the day is done."

Tabitha's sisters released her, and she fell sideways. A river of her brother's sperm seeped down her leg. Hope fell forward and hugged Michael.

"Such a good job," Hope said, "I knew you could do it." She kissed his head in that motherly way again.

"You think that was good, you should try his tongue," Chastity said.