Every character in this story is 18+. It contains snuff and incest unless you don't think clones count. And if you don't think clones count, how dare you? They're just like you and me.
The man-size glass tube and its attached console had not only taken over most of Cory’s small bedroom, it had also taken over most of his life. His father’s prototypes were beta tests disguised as presents to his two children so Cory’s daily and nightly use of the Intercourse Partner Synthesizer was mutually beneficial.
The holographic preview inside the tube showed a cute girl with short blonde hair. Naked and hairless, she stared blankly at Cory through the glass, waiting for a press of the big green button that would bring her to life. “Life” might have been an overstatement; synthesized humans were composed of the same combination of atoms but there was nothing to suggest they had feelings… other than the ones they were programmed to have. No sentient being would willingly return to its tube after a set timer to get dematerialized.
Cory was happy with his settings. He had given up on the face (good enough) but often tweaked the body to look a little more like Kim each time. The hatred for his sister had been had taken an interesting twist when he caught a glimpse of her slipping out of a wet swimsuit through the crack of a door. His feelings had been more... complicated since then.
He made the ass a little rounder, the perky breasts a little bigger, rotated the hologram, then nodded in satisfaction. As he was about to press the green button, however, a tiny triangle arrow on the console gave him pause. “Another preset?” Cory had always edited the same save file.
The holographic doppelganger flickered and a semitransparent projection of Kim took its place in the tube. No matter how many times Cory blinked, his sister remained in there, smiling. This was not someone else’s attempt at creating a replica; this had to be a scan. Kim must have just entered her own device and scanned herself, an option he had himself dismissed as useless. Submissive, sensual, quiet, susceptible to pain… the default personality settings worked fine for Cory. It turned him on to assume Kim had set these herself to mirror her personality. He slammed the green button and the glass frosted to hide the creation process and rushed to take his clothes off to be as naked as the brainless simulacrum about to emerge.
Through the lingering smoke of her creation, Cory’s growing erection was the first thing Kim2 had ever seen. She did not know it was activated by her perfect likeness, down to each beauty mark and areola bumps, to a real girl in the room next door.
“Morning, Kim. Why don’t you pretend I’m one of your teachers and you had a B on your last assignment?”
The synth was confused by the command. She was blissfully unaware that the original Kim was a straight-A student or the resentment it spawned from her academically less successful brother.
“Get on the bed, slut!” Cory gave her a command she could better understand and watched the jiggle of her breasts as she took her very first clumsy steps before climbing on the bed.
“Say that you’re an attention whore.”
“I’m an attention whore,” the synth repeated with Kim’s voice. Cory’s cock twitched… That one detail was impossible to get right without a scan. The value of Kim’s real voice in this fantasy scenario would make an immeasurable difference. This was the greatest day of his life.
“You’re a regular whore too, I bet,” he continued. “Get on the bed, tits-up, and open your mouth wide.” Kim2’s 2-minutes-old breasts swayed but remained defiant against gravity as she settled on her back. Her big brown eyes of the perfect shade looked up at him upside-down. Normally, Cory would rush right to his favorite part but this fresh body was begging for further exploration as long as he could keep half of his mind elsewhere for fear of premature ejaculation.
His hands started on the young girl’s tummy, feeling its rise and fall from her nervous breaths, then glided up on the soft lifelike skin. Her breasts had grown bigger since the fateful day he caught her changing but were just as perky as they were in his spank bank. The puffy areolas were pale, almost pink and it was such a joy to squeeze them between thumb and index and twist to hear Kim’s squeal. It wasn’t much more than a soft moan because of the quiet mode but her body contorted in simulated pain (or pleasure, what difference did it make).
“What are you going to do, huh? Tattle to dad like you always do? How are you going to do that with my cock in your throat?”
Without letting go of the stretched up, twisted tits, Cory straddles the face of his sister’s ephemeral clone. Her mouth had not closed since he ordered it open and fit his large erection perfectly. Though all he could see of her head was a chin and a bulging frog throat, it was still easier than ever to convince himself the real Kim was pinned down, struggling for air.
With some wiggling and a strong push of his legs, Cory punched the whole length of his shaft down her gullet. He had forgotten to check the throat settings but they were just the way he liked it; the scan had determined Kim had a strong gag reflex. She glugged and clucked and the spit coming out of her nostrils ran down her assailant’s swinging balls. This was Cory’s little slice of heaven and there was only one thing left to do before releasing his pent-up emotions in an explosion of jizz down the constricting canal.
With weak, flailing limbs, the newborn Kim hopelessly tried to tap out, unknowingly enabling Cory’s roleplay. His fingers had left red lines on the white meat of her breasts and were now tight around her neck; so tight that it was practically a two-handed handjob with the cock moving instead.
His hatred and lust for his sister were one in this unspeakable act. Like a trigger, Cory filled her stomach with his incestuous seed when Kim2’s throat relaxed and her arms fell limp to against his thighs. All he had to do afterward was drag the synth back into the tube by the leg and press the red button. A minute later Kim2 was returned to her basic components and, two minutes after that, Kim3, wide-eyed and innocent, was smiling at him from the smoking tube.