As you were witnessing how the various household members were augmenting their forms using body parts borrowed from the ubiquitous clones of Teri, your own trillions of bodies were sharing in carnal pleasures throughout the house. Even now, you were feeling countless blowjobs, tentacle-jobs, handjobs, slime-jobs, tail-jobs, and numerous other activities, to say nothing of the rest of your generously endowed bodies being used in selfcestual acts of debauchery. Before you could think of another way to utilize the app, another wave of thousands of simultaneous ejaculations and orgasms crashed through your shared senses, causing you to multiply into the high quadrillions.
Meanwhile, Sarah was reveling in the opportunities offered by converting Teri's three headed, eight-armed, six-breasted hermaphroditic form and its detachable parts, but she quickly wanted more. For a while, she imitated the method of duplication she saw you helping the shortstack with, but eventually she found a much faster method. As an experiment, the kitsune pulled off her middle head while envisioning detaching her whole body from her head. To her glee, the head in her hands started regrowing an entire new copy of her body, complete with the other two craniums next to it. Pushing it further, she then tried to remove all three heads at once, successfully creating three new clones at the same time. After a few simple head detachments, she was able to place new noggins on the bodies she used to generate the clones, and now had five bodies to repeat the process with.
However, heads certainly weren't the most numerous thing on her bodies, Sarah thought as she waved around her fluffy tails and prehensile cocks. Testing to see if her other copies could remove parts for her, a sextet of her bodies surrounded another one and pulled on all eighteen appendages growing out from her backside and crotch. Sure enough, the tails and flexible dicks came off easily, and soon she had eighteen more duplicates, each one rubbing her hands along her voluptuous form as she licked her lips at the thought of how many more of herself she would make.
That said, Sarah needed to make sure her body was the best it could be before she started multiplying in earnest. To that end, all of her bodies derived from Teri's started detaching parts from themselves and reattaching them elsewhere on their bodies, careful to keep them all identical. First, she gave herselves a fifth pair of arms, then two more copies of Teri's original, huge cock. Next, she peeled off two mouths to place them on her top pair of breasts, giving herself lipples. Instead of doing the same for the lower pairs, she first placed a copy of her pussy on either side of the original, then copied all three to put on her middle-left breast. Shortly after, her middle-right tit got the same treatment, which just left her bottom pair. Following the pattern, she detached all three of her large human dicks to place on one boob, and then the other. However, she wasn't done yet. Detaching her tongue, she waited for it to grow back before attempting to stick the removed one to the end of the new one. To her delight, the two merged to make a double-length tongue, the width balancing out in the middle to make it look like it was naturally that long instead of one tongue stuck to the tip of another. Not wanting to make it too long that she couldn't keep it in her mouth, she instead turned her attention to her lipples, where she not only tripled the length of their tongues, but also added two more tongues in each. Meanwhile, she didn't make her palm-mouths' tongues any longer, but still doubled them.
Perhaps for most people, this would have been enough already, and very likely too much. However, a lesser known side effect of being a kitsune was possessing lust proportional to the number of tails possessed. And with the normal maximum of nine, Sarah already was a bottomless pit of carnal desire. Deciding on her next change, she detached all three of her left breasts. Once they grew back, she put them all back right between each pair, giving herself three rows of three boobs. Inspired by the numerous bodies she had that were copies of your current form, the foxgirl detached the rest of her body from her right leg, then attached the whole thing to another body's left thigh, essentially making herselves conjoined twins with three legs. Repeating the process, this time leaving behind the left leg, she gave the second body another torso to the right, giving herself a third torso and a fourth leg.
Admittedly, you found the show incredibly erotic somehow, and you couldn't help but cum with the eight bodies you were watching with, including the one holding the phone. As you tilted your heads back and closed your eyes while riding the euphoria, you suddenly felt some soft, fuzzy tails wrap around your body from behind. Freezing up, you suddenly worried what would happen if Sarah were to convert your body into one of hers. Would she quickly figure out how the app worked? Would she immediately gain the knowledge of everything done with it so far? Or would you be protected somehow?
As your mind swam with these questions, you heard your own voice ask in a sultry tone, "My, such a cold reaction to being touched by a beautiful woman, maybe I could help you loosen up?" Gently grabbing your shoulder along with one of Mona's shoulders, she used her tails to assist in spinning you around to face her. Looking directly at her, you saw that it was Sarah's original body, all three of her pairs of eyes staring intently into your own. "Might it be that you have something to do with these delightfully sexy bodies everyone has?" she asked as three of her hands traced your jawlines sensually.
"H-how did you know?" You asked, sweating and confused.
Chuckling in triplicate, the sly fox responded, "I didn't, but thanks for confirming." Hearing this, both you and Mona grimaced at your slip-up. Speaking with her left head, Sarah continued, "I merely had a hunch based on what I've observed." Switching to her right head, she explained, "How can a kitsune have nine tails already while her mother is still in her forties? Why do I look nearly identical to someone who lives a few blocks away despite no blood relations? How is it that most animals require food in proportion to their body mass, while a hydra with several thousand upper bodies only needs to eat one meal?" Leaning in close, each of her heads whispered in sync, """Need I go on?"""
Knowing how these situations usually went in stories, you nervously cut to the chase, "W-what did you want from me?"
Pulling away, but still keeping her tails in contact with you, Sarah replied simply, "Your help." Seeing your raise an inquisitive eyebrow, she expounded, "I merely wish to experience the ultimate pleasure." Proceeding to switch which head she spoke with mid-sentence, she continued, "Continuing to multiply," "-being able to convert clones of other people into new bodies for myself..." ""Both feel amazing."" Sighing, she added, "Be that as it may, I am at the mercy of the limits of the bodies I copy." Continuing her tricephalic soliloquy, she stated, "As much as I'd like to," "-I can't merge bodies with different forms..." "I can be an insectile drone," "a scylla," "or a slimegirl," """but never all three at once.""" Stroking her tails along your arms, she added, "And some bodies are completely off limits, such as my hydra-mother's lamia body, since converting her would essentially mean her death."
"So, what would you have me change?" you asked, figuring you had no choice but to play along.
Reaching out to caress your body with a few hands, Sarah responded, "Quite simply, I want to be able to freely combine my forms, and gain those of others without worrying about consequences."
Swallowing hard, you told her, "Well, I can certainly try, but there's a degree of randomness to the kinds of changes I can make to people."
Smiling with all three of her mouths and both her lipples, she answered, "That's fine. Keep doing your thing and make more wondrous creations for me to adapt to myself. Just do what you can to fulfil my desires." Her tone getting more serious, she added, "But if you instead try to cross me..." Suddenly, you felt five hundred of your other bodies start turning into clones of Sarah in unison as an equal number of kitsunes ran their tails along your bodies. """I just might convert every. Last. One. Of you."""
Nodding profusely as you held back a moan from the feeling of so many conversions at once, you agreed, "I'll do my best."
"Excellent!" the foxgirl exclaimed before leaning in and kissing all three of your heads passionately. """Also, if you do as I ask, I will make you feel pleasure that no other human has ever felt before,""" she whispered with all three mouths before withdrawing her tails and winking in triplicate. As she began to walk away while swaying her hips, it didn't escape her notice when you lifted your phone to check the app. Selecting Sarah as the target, you generated a sentence about the cunning kitsune.
"This kitsune is excitedly dreaming of all the sexy bodies she wanted for herself."
Thankful that the app immediately gave you something you could use to fulfil one of Sarah's demands, you changed "wanted" to "copied", but stopped yourself before submitting. How the changes worked so far, the targets weren't aware that reality had changed, so how would Sarah know that you made the modification she asked for? As you were thinking this, you noticed the settings that you had mostly ignored so far. Thinking back, you recalled the advertisement in the shop for the app listed change awareness as one of the options you could set. Opening the sidebar, you confirmed that there was indeed a set of checkboxes for whether you, the target, or the world at large would be aware of the changes. Tapping the box for "target", you made it so that Sarah should be aware of the modification, then submitted the sentence. Suddenly, reality shifted to grant Sarah the new ability, and your eyes met hers. Grinning widely, the foxgirl nodded at you to confirm that she realized what happened.
Wasting no time, Sarah had one of her bodies embrace one of Erika's torsos and activate her new ability. Before your eyes, you witnessed her legs gradually shift into a long snake tail. As it kept growing longer, her body shifted to copy the lamia's current form, complete down to having three miniature copies of herself as dicks with numerous cock-tails coming out of their backsides. Next, her body rapidly began subdividing repeatedly, creating conjoined snake necks until she had over seven thousand of them. With her vastly expanded form now wending its way through numerous rooms of the house, it was very easy for the kitsune to touch it with a few hundred more clones of herself. Soon, she had that many more hydra-lamia bodies, their thousands of branches hopelessly tangled together as they had sex with each other, causing them to split further.
No doubt showing you a taste of her thanks, Sarah dragged tens of thousands of your other bodies into the sex, and lovingly massaged you all over while kissing you, riding your dicks, licking your pussies, and performing thousands of other pleasurable acts. So coordinated were her efforts that you all came in unison, causing every clone of you to multiply into over fifty thousand more. "Just a taste of what awaits you if you complete my request," the fox lilted lustfully. Not wanting to disappoint her, you hastily procured another new sentence to work with.
"Mrs. Johnson is getting played with by this kitsune's eight tentacles."
Unfortunately, try as you might, you just couldn't come up with any way to make this into a sentence about merging Sarah's bodies. Settling for improving her a different way, you changed "eight" to "numerous", but forgot to turn off awareness before sending it. Suddenly, it seemed as if all of Sarah's scylla bodies were a bit taller, and you saw it was because she now had a lower half more befitting of a kraken. Finding it impossible to get an exact count with how they all kept wriggling and shifting around, you estimated that the kitsune must have had around forty tentacles, each one about twenty-five feet long now.
As Sarah used her rubbery new limbs to violate four more of your clones, she remarked, "Hmm, I don't recall asking for this, but I do rather like it regardless."
Chuckling nervously, you replied, "Like I said, there's some randomness to what I can change. I'm definitely still trying."
"And I'm sure you'll succeed, don't worry," the other woman said before planting a trio of kisses on your lips. Elsewhere, you could see through your other bodies that many Sarahs were wrapping numerous tentacles around her Teri-bodies to efficiently start more multiplications of them, and many of her hydra-torsos were sensuously embracing her kitsune clones derived from your succubus-conjoined form.
When you tried again with another sentence, you received the following:
"This kitsune is pleasuring herselves by pressing many different bodies together."
Not one, but two verbs in this sentence, and it was for Sarah-on-Sarah action, this was perfect. Pondering which word to change, you realized that if you left "pleasuring" alone, it would probably make it more erotic for Sarah to combine her bodies. Making a suitable edit, the new sentence read:
"This kitsune is pleasuring herselves by merging many different bodies together."
Accepting the change, you witnessed as Sarah's hydra-lamia body absorbed the part-succubus into herself, causing her to get two conjoined torsos with three heads each. As their forms continued to blend, the new torsos each gained a trio of mini-Sarah cocks while all three of her upper bodies gained their own regular-sized cock-tails. To your surprise, the change then propagated to the rest of her branches, causing them all to have three torsos at the end of their snake necks. As the process finished, her thousands of torsos experienced a massive orgasm from the pleasure of melding together, triggering the whole body to split of a new clone. Likewise, the scylla-Sarahs merged with the detachable Sarahs, keeping the normal height and losing the shortstack build while gaining an extra pair of arms and all the changes to her mouths, breasts and genitals while gaining two more torsos. As a test, she proceeded to detach a dozen of her tentacles before reattaching them nearby, successfully adding to how many she had and smiling widely.
Very much aware that her wish had been granted, countless clones of Sarah all looked your way with lust in their eyes. Next...