An Experiment in Incest

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Sex between brother & sister, mother & son, and BIL & SIL.
13.2k words
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There are no characters under the age of 18-years-old in this story.

*

Keeping it all in the family is the incestuous plot of this story. The adult family that has consensual sex together stays together. Sex between a brother and sister, and a mother and son, before stretching the definition of incest to include a brother-in-law sexually seducing his sister-in-law, a sister-in-law with her sister-in-law, and a son-in-law seducing his mother-in-law.

Author's Note: This is an incestuous, sexual encounter that really happened between a brother and sister, a mother and son, a sister-in-law with her brother-in-law, a sister-in-law with her sister-in-law, and a son-in-law with his mother-in-law. This is a true story. The names have been changed to protect the privacy and the true identities of those in the story.

* * *

As if daring him to do so, egging him on, something that was as sexually exciting to some as it was nasty to others, Mark's sinister, sister-in-law, Colleen, baited her husband, Alec, to seduce his sister, Claudia. Seemingly, she took some sort of sexual satisfaction in pitting one person against the other. Biding her time while waiting for the right opportunity to present itself, she watched Claudia swimming back and forth by her brother. As if sexually teasing him, while unknowingly exposing much of her naked body to him, Claudia was having fun swimming.

She didn't have a pool and every time she visited her brother's house she enjoyed going for a swim. With San Diego not as hot as the rest of southern California, it does get hot enough during the late summer months and the fall to enjoy the relief of a pool. She wished her husband would agree to a pool but his excuse was not having the time nor wanting the expense of the maintenance.

Obviously, being that Claudia didn't always get along with her sister-in-law, she'd rather spend her time visiting by swimming in their pool than sitting at the patio table listening to Colleen talking shit about everyone. Always needing to play her head games, this time she was getting in her husband's head by sexually tempting him to have sex with his sexy sister. Adding fuel to his incestuous fires, Colleen knew that in the way that he had always been sexually attracted to his mother, he had always been sexually attracted to his sister.

Obviously, even though she'd never admit it, rather than to face the rejection, it bothered Colleen that her husband sexually wanted his mother and his sister seemingly more than he sexually wanted her. Perhaps, if she wasn't such a conniving bitch, her husband would love her in the way that he loved his mother and his sister. Yet, unable to help herself, not a woman to be sexually rejected, she was always trying to get back at him for his incestuous, sexual selections.

While patiently waiting for her perfect opportunity for her husband to join his sister in the pool, Colleen could clearly see that Alec already had an erection in his bathing trunks. Obviously, he was sexually excited from watching the nearly naked, swimming show of his sibling. She swam back and forth in front of her brother while unaware of the wardrobe malfunction of her bathing suit.

"Look at your whore of a sister," said Colleen to her brother while glancing at Claudia's husband, Mark, to see his reaction to her calling his wife a whore. "With her breasts hanging out of her bathing suit and her nipples already erect, she's begging for you to touch her big tits. With much of her ass exposed, tempting you to do so, she obviously wants you to touch her, feel her, fondle her, and squeeze her ass. In the way that her bathing suit barely covers her pussy, she obviously wants you to finger her before fucking her," said Colleen.

Mark watched his wife swim by them.

"That bathing suit does leave nothing to the imagination," said Mark with a dirty laugh while eying his nearly naked wife. "Clearly, she literally is quite exposed. With her always so modest, I wonder if Claudia even knows how much she's unknowingly showing her brother."

Colleen looked at her husband and touched his bare leg before putting her hand on his bathing suit clad erection.

"Go on, Alec. Join your sister in the pool. Swim with her," she said squeezing his cock. "Do it. You have my permission to touch your sister and feel her," said Colleen.

Alec looked at his wife with shock.

"I do?" Alec looked at his wife with surprise. "You don't mind if I have some sexy fun with my sister?"

Colleen shook her head.

"Of course not. She's your sister and you're her loving brother," said Colleen. "What's wrong with that?"

Alec looked from his wife to look at his brother-in-law, Claudia's husband.

"Is it okay if I touch and feel Claudia?"

Mark gave his brother-in-law a smile.

"Be my guest. With her already showing you most of her naked body, I'm sure that's what she wants," said Mark with a disinterested shrug.

Alec seemingly couldn't believe that he had the permission of not only his wife but also of his brother-in-law to touch and feel Claudia.

"For her to expose herself in that sexy way, she obviously wants you to touch and feel her," said Colleen pausing to watch her husband's reaction to seeing his nearly naked sister. "Now is your chance. I dare you to put your erect cock in her hand. Maybe she'll stroke you. Maybe she'll give you a hand job. Wouldn't you like a hand job from your sister? I know you would," said Colleen.

Seemingly surprised that she was giving him her permission to sexually molest his sister, Alec looked from Colleen to stare at Claudia before returning his focused attention to his wife.

"No. I can't do that, not in front of Mark," he said. "I would if I was alone with her. I'd touch and feel Claudia everywhere. I'd even fuck her, I would," said Alec while looking at Mark's reaction to him wanting to fuck his sister.

Colleen laughed.

"Don't be silly. Mark won't mind you having some sexy fun with your sister. Besides, between the couple of drinks that she had and the marijuana laced brownies I made and she ate, she's obviously high enough not to realize she's as exposed. She wouldn't even know that you were touching her and feeling her. Go ahead, I dare you to fuck that little whore," said Colleen fondling the head of her husband's prick through his bathing suit.

Alec looked at his wife with as much hatred as he looked at Claudia with lust.

"Stop it, Colleen. I won't allow you to call my sister a whore," he said sticking up for his sister when her husband failed to stick up for his wife. "She's not a whore. She's a good woman."

* * *

Alec watched as his sexy sister swam by him in the pool again and again. Obviously, his wife was right. The first time seeing as much of his sister's nearly naked body, he could clearly see his sister's big, naked tits and her erect nipples. He could clearly see the full, roundness of her naked ass. He could clearly see her pussy.

As if inviting him to finger her, lick her, and fuck her, he stared at his sister's naked, bushy, brown pussy. The more that he saw of his sister the more sexually aroused he became. Now with his wife holding his cock in her hand while whispering her sexual suggestions in his ear of what he should do with his sister, he had quite the erection. As if begging him to join her, the last straw was when Claudia swam by him doing the backstroke with her tits and pussy completely out of her bathing suit and floating on top of the water.

"Oh, my God,' he said while watching his nearly naked sister swimming by him kicking her legs. "'I can't believe I'm seeing my sister's naked tits. I can't believe I'm seeing my sister's naked pussy," he said in a mumble as if talking to himself.

Giving him her approval and her blessing, obviously his wife wanted to watch him touch her, feel her, fondle her, and fuck his sister. Knowing full well that his wife was bi-sexual, perhaps, she'd vicariously gain some sort of sexual satisfaction out of watching him having his wicked, forbidden, sexual way with his sister. Perhaps, after he was done groping his sister and fucking his sister, getting her ready for Colleen to take over, she'd want to eat Claudia's pussy. Perhaps, hoping that she was high enough, she hoped that Claudia would return the sexual favor and eat her pussy too.

Never without a diabolical plan, Colleen enjoyed not only sexually exciting and sexually teasing those around her but also sexually humiliating those closest to her. She had a habit of pulling the rug out from under someone when they thought they were about to get what they wanted. This time it was her husband, Alec, and his sister, her sister-in-law, Claudia, who were at the center of her sexual scheme.

Obviously, her prize, after her husband had sex with his sister, was her having sex with Claudia's husband, Mark, her brother-in-law. Then, after she had sex with Mark, hopefully with Claudia high enough and sexually excited enough from Alec getting her ready and in the mood, she'd have sex with Claudia too. Obviously, as much as she wanted to eat Claudia's pussy, she wanted her sister-in-law to lick and finger her too. Seemingly, Colleen would have sex with anyone if it pleased her and/or moved her personal agenda forward.

"Watch this," she said leaning to whisper in Mark's ear as Alec eased himself in the pool to swim alongside his sister. "A long time coming, with incest the best, life doesn't get any better than this," she said turning to look at Mark. "With my husband about to grope your wife and have sex with his sister, that opens the door for us to have sex," she said giving him the eye. "That opens the door for me to have sex with Claudia too."

Mark watched Claudia's brother swim closer to his sister as if Alec was a shark and she was a helpless seal.

"Knowing her as I do, if she wasn't tipsy from drinking and high from eating your brownies, she'd never allow her brother to sexually touch her," said Mark. "If she's anything, she's a prude. Not only won't she give me oral sex but also, she won't allow me to give her oral sex," he said looking at Colleen as if expecting her to blow him. "Good luck in trying to allow you to give her oral sex and in trying to get her to give you oral sex."

When Mark turned and looked at Colleen with an expression of shock filled with sexual excitement that his wife may allow her brother to touch her, feel her, and possibly even have sex with her, she suggested the finale.

"Tell me and be honest," she said teasing Mark with a sexy look and a naughty smile. "Wouldn't you like to watch me eat your wife's pussy? Wouldn't you like to watch Claudia finger and lick my cunt?" Colleen let out a loud cackle. "Wouldn't you like to watch me make her my lesbian whore?"

* * *

Incest was hard for some to imagine. If it wasn't shocking enough that an adult, married brother would want to have sex with his adult, married sister, it was even more shocking that a wife would not only approve but also encourage her husband to solicit his sister for sex. Obviously, incestuously inspired by a brother's love for his sister, this was Colleen's sexual, master plan all along. She not only wanted to watch Alec groping Claudia before having sex with his sister but also, Colleen wanted to have sex with Claudia's husband, her brother-in-law, Mark, before she had sex with her sister-in-law.

The icing on the incestuous cake with Claudia's lesbian cherry on top, was Colleen fingering and licking Claudia's pussy in front of Mark and Alec. Obviously, she'd love to see their reaction to having lesbian sex with the stuck-up and morally superior Claudia. As her sexual finale, she'd obviously love nothing more than to get Claudia to finger and lick her pussy in front of Mark and Alec too. In the way that she wanted to give Claudia a sexual orgasm with her fingers and tongue, she wanted Claudia to give her a sexual orgasm with her fingers and tongue too.

What kind of wife is she that she'd not only approve of her husband having incestuous sex with his sister but also encourage her man to have sex with another woman? What kind of woman is she that she'd want to give Claudia oral sex in front of her husband and brother and want Claudia to give her oral sex in front of them too? What kind of world is this that incestuous, sexual, relationships reign supreme? Have they no shame? Seemingly, expanding forbidden sex to include sisters-in-law, brothers-in-law, and mothers-in-law, every man seemingly wanted to have sex with his mother, his sister, his aunt, and/or his cousins before having sex with his in-laws too.

A sexually, incestuous conspiracy incubated between Colleen and Mark, Claudia's husband, mostly Colleen, as if planning a surprise party, they talked about their demonic, sexually incestuous plan in hushed whispers. They watched as Alec made his sexual move on his sister while they were innocently swimming in the pool. Seemingly, whether groping her and/or fucking her, Colleen enjoyed the sexual scenario of watching Alec having his wicked, sexual way with his sister.

Only, a small complication, Corrine, Claudia and Alec's mother, Colleen and Mark's mother-in-law, turned up unannounced and uninvited. Obviously, in the way that Colleen was too, Corrine was a woman not to be ignored. Adding fuel to the incestuous fires, years ago, Corrine had previously involved herself into this incestuous conclave by giving her son-in-law, Mark, a blowjob, before turning her sexual attention to her son, Alec.

She had always sexually teased and flashed her son but tonight, there was much mutually consensual, incestuous inspiration in the air. Tonight, not only would Alec hopefully have sex with his sister but also Colleen would hopefully have sex with her brother-in-law and her sister-in-law while Corrine had sex with her son and son-in-law. But for Claudia, with every family member complicit in their incestuous relationships with one another, there was no guilt, shame, or remorse. Claudia was the last holdout in Colleen's incestuous, sexual plan. Having drugged her with marijuana laced brownies, Colleen was obviously hoping to inoculate Claudia in their incestuous club by encouraging Alec to have sex with his sister.

"Trust me. Incest is the best," said Colleen to Mark. "As I said before and something that I've always said, the adult family that has consensual, incestuous sex together, stays together. The adult family that has consensual, incestuous sex is a happy family without being sexually frustrated by lusting over forbidden, sexual relationships," she said to Mark while waiting for him to agree. Why shouldn't mothers have sex with their sons, sisters have sex with their brothers, brothers-in-laws have sex with their sisters-in-laws, sisters-in-laws have sex with their sisters-in-laws, and mothers-in-laws have sex with their sons-in-laws?"

As if already hypnotized by his sexy sister-in-law, Mark nodded his head in agreement. Yet, aside from his brother-in-law wanting to have sex with his sister-in-law, if only Alec knew that his mother sexually wanted him as much as he wanted his sister, what would he say? What would he do? Would he fuck his mother in the way that he was determined to fuck his sister?

Obviously, this family seemed driven by incestuous thoughts, sexually inappropriate actions, and incestuous sex. This family felt it appropriate to not only have sex with their blood relatives but also to expand their ring of sexual debauchery by including their forbidden sex to their in-laws as well. With them already expanding their incestuous circle of lovers, it's a good thing that Mark, Colleen, Claudia, and Alec didn't have any more brothers and sisters living nearby. Alec and Claudia's sister, Maggie, was living safely on the other side of the country in South Carolina.

* * *

Colleen and Mark sat across from one another on the patio while watching Claudia and Alec having some innocent, albeit incestuous fun in the pool. Not bringing her bathing suit, part of Colleen's devious plan, she told Mark not to tell his wife that it was a pool party. Instead, Claudia borrowed a one-piece bathing suit from her sister-in-law, Colleen. After having recently lost some weight, Colleen purposely gave her sister-in-law a bathing suit that was even too big on her.

"Gees, Colleen, this suit is way too big. I'm hanging out everywhere. Everyone can see everything I own," said Claudia.

Claudia looked at herself in the mirror while turning one way before turning the other.

"Don't worry about it, Claudia. Who's going to see you? Your husband? Your brother? It's just the four of us. With you growing up with one and married to the other, you're not showing any more than what they'd already seen of you before," said Colleen.

Claudia continued looking at herself in the mirror.

"I don't know, Colleen. My tits are hanging out on top and my ass and pussy are exposed on the bottom," protested Claudia. "I suddenly feel like Venus or Aphrodite wearing an abbreviated toga that doesn't completely cover me. I feel like a Playboy Bunny at one of Hugh Hefner's Playboy mansion parties. I feel so naked. I feel so exposed."

As if she was a man looking at a naked woman, instead of a woman looking at her sister-in-law, Colleen stared at all that Claudia was showing. As if committing the images of her nearly naked sister-in-law to memory, she stared at Claudia's tits, areolas, and nipples. She stared at Claudia's nearly naked ass and she stared at her sister-in-law's exposed pussy.

"Don't be such a prude, Claudia. Besides, it's already dark outside and you'll be in the water. I won't turn on the pool light to spare your modesty and to give you the privacy that you obviously need when swimming. Then, as soon as you get out, I'll have a towel ready for you to wear. Trust me, no one will see anything of you that they shouldn't see."

With Claudia barely 5'2" tall and smaller boned, and Colleen a statuesque, model like, 5'8" tall and bigger boned, not how a bathing suit should fit, the bathing suit was not only loose in the crotch but also loose on top. Had Claudia been sitting on the patio with Colleen and Mark, with every move she made, she'd already be flashing her brother her big tits, her brown, bushy pussy, and her naked ass. Had she not been submerged in the pool water as soon as she walked outside, her brother would have already seen every part of her naked body.

* * *

"Marco," said Claudia.

Alec swam closer to the sound of his sister's voice while his sister swam further away. Leading him to the darker and deeper end of the pool, she seemingly wanted to be groped by her brother as much as her brother wanted to grope her. Only, her husband knew his wife better than that. If anything, she was a sexual prude, especially when it came to incestuous sex. If anything, their sister-in-law, Colleen, along with their mother, Corrine, were the real whores in the family. Perhaps the two drinks she consumed and the marijuana laced brownies she ate were adding to her uncharacteristic horniness.

"Polo," said Alec with his eyes closed and his hands reaching out to grab whatever he could feel of his sister.

Then, with Alec having one too many beers and horny to begin with, letting it all hang out in the way that his sister was, he removed his erection and his testicles from the netting of his bathing suit. Now, once he grabbed hold of his sister, he'd be rubbing his naked prick all over her thighs, her ass, her exposed pussy, and her belly. As if his sister was his sexual prize, once he grabbed hold of Claudia, his brotherly touches would immediately change from innocent fun to incestuous groping.

The tops and the sides of his sister's big tits spilled out of her top and were nearly nakedly exposed from her ill-fitting bathing suit. Especially with the water puffing out the extra material of her one-piece suit, at first, even after seeing so much of his naked sister, Alec made his innocent gropes appear accidental. With so much of her tits nakedly exposed, it was easy for him to take a handful of his sister's big breasts in his horny hands without her even noticing.