Sister’s Magical Whoopsie.

Synopsis: Nina’s twin brother buys her an old spellbook as a prank for their shared eighteenth birthday. What should have been a silly game quickly spirals out of control when the magic is released. Themes include mind control, ****, male growth, breast expansion, and bimbofication.

Sister’s Magical Whoopsie.

“Oh no, this is bad. This is really, really, bad!” Nina whimpered, crouching beside the window and flipping desperately through her spellbook. “C’mon, there has to be a way to fix this!”

The old tome in her trembling hands was meant to be a joke—a gag gift from her twin brother Trevor to liven up their shared birthday. He’d said he bought it from a new second-hand bookstore across town.

A new store selling used goods had sounded odd but ultimately harmless in the greater scheme.

Except now, Trevor was next door plowing their neighbor, Mrs. Hatcher, over her kitchen island. Nina could see them clearly from her position, straight through the floor-to-ceiling French windows the middle-aged woman had installed last summer.

She’d said they provided more natural light. Today, they just gave Nina an unfettered view of her brother hammering the mature beauty’s well-padded rump from behind–her pastel sweatpants and boring panties ripped to tatters by Trevor's bigger, stronger hands–as she wailed out raptures of pleasure.

“Oh fuck! That’s it, hunk! Smash my married pussy with that amazing dick!”

Mrs. Hatcher’s dark hair was a touseled mess, fanned out in silky mahogany strands over the marble countertop, and her large, springy breasts were squashed flat against the surface in the solid black sports bra. Each rampant thrust from Trevor rocked her entire body forward as if she would go flying were it not for her white-knuckled grip on the opposite edge.

“Yeah, take it, you MILF whore. Take my hard cock and tell me how much better I fuck than your dweeb husband!”

“Sooo~ much better… Oh god!” She cried, quaking with her fourth orgasm since he had barged into her suburban home twenty minutes earlier. “That shrimp-dicked wimp never had the balls to pound me like this!”

Trevor barely resembled the newly eighteen-year-old boy he had been that morning.

The thoughtful, contemplative youth with a runner's physique had… swollen–no other word for it–before Nina’s eyes into a muscle-bound monster that had burst from his flannel pajamas like something from a cheesy horror flick.

Oh sure, the coppery hair they shared was still the same, and his sage green eyes were unmistakable, but otherwise, Nina’s twin was a remarkably changed man.

Trevor’s back was an avalanche of rock-hard muscles, broad as a barrel and rippling with inhuman strength as he ravished their ecstatic neighbor with pummeling stabs of his enormous manhood. His glutes flexed most distractingly, and dimples formed above each hemispheric cheek.

Wide shoulders that could lift the heavens and heavily shredded limbs to match rounded out a chiseled appearance that would spark envy in world-class bodybuilders or the actors in those gladiator shows he watched.

Even his weak jawline had morphed into an anvil coated in ginger stubble that was fast becoming a proper beard.

And it was all because of that awful book and the stupid spell Nina had cast as a joke.

It was a dusty grimoire, so ancient the title was worn off the leather cover and spine. It contained some odd illustrations and decorative borders–Trevor had called them illuminations–and the language was foreign, with squiggly lines, dots, and circles above many letters.

“Ha, found you.” She gasped in relief, finding the page that had kicked-off the madness. It was yellowed with age, and the ink faded in parts, but the heading was still legible.

Blezun Hildisvíni

A picture in the top corner showed a blonde goddess bedecked in a cloak of flacon feathers, resting a glowing palm on the snout of a car-sized boar. It had seemed innocent enough at the time, and Nina had giggled through the incantation, doubtlessly mangling the pronunciation and pressing a finger to Trevor's nose in a similar fashion.

She wasn’t laughing anymore.

Trying to block out the sound of her twin railing Mrs. Hatcher to fresh heights of carnal depravity, Nina studied the spell. Looking for any clue to undo the chaos she had wrought. The recent memory of watching them rutting like beasts didn’t help her concentration; the slapping of their firm flesh colliding was like a thumping bass line in her skull.

“Here it comes, you horny slut!” Trevor’s deep, masculine roar rattled the window panes. “Gonna stuff that fertile MILF womb with a gallon of my goddess-blessed seed!”

“YEEESSSS~!! Do it, you incredible hunk! Knock me up!”

The alien words swam on the page, and the image of the goddess turned to grace Nina with a beatific smile…

Clothing was strewn across Nina’s bedroom like shrapnel after a bombing.

Skirts, dresses, tops, and underwear lay in crumpled heaps on her bed and floor. She had plundered her wardrobe, drawers, and hangers in a feverish fit, not knowing what she sought but searching regardless.

The final verdict had been her high school uniform for some unknown reason.

It shouldn’t have fit. By all accounts, Nina was a late bloomer, rake-thin and boyish in figure, only growing marginally in her chest and lower half after graduation.

The sized-for-teen white schoolgirl blouse and red tartan necktie buttoned tight across her meager handfuls, exposing a swath of her featureless tummy. A dismally short pleated skirt hung from a nearly non-existent waist, barely covering her trim upper thighs. White knee-high socks and tennis shoes adorned Nina's pale legs and dainty feet.

As for underwear…

Underwear was proving to be a dilemma.

Every sensible pair of briefs or boyshorts Nina had so much as touched made her skin itch like the devil. Only the teensiest crismon thong she didn’t remember owning was tolerable as a minor footnote concealing her nethers.

Bras were equally troublesome, to the point she had gone without and let her little beesting breasts rub against the starchy cotton top. Her nipples were two pink diamonds poking through the taut fabric.

Nina couldn’t rightly fathom why the change in outfit was important, only that it had felt crucial at the time. The powerful compulsion to appear, if not exactly sexy–she had never been that–but more… available for a big, strong man’s viewing pleasure was irresistible.

Now that it had passed, she could return to the tricky task of deciphering the spiraling words of the spell, smiling at the winking goddess, and occasionally stealing peeks of Trevor destroying their smoking hot MILF neighbor’s pussy.

Except he wasn’t balls deep in Mrs. Hatcher’s gushing cooch anymore. He had flipped her over with effortless ease, then climbed onto the countertop to straddle her fat mommy titties and jam his gigantic, cum-slathered cock between them.

The first plunge of his mighty hips obliterated the sturdy black sports bra like it was nothing.

Nina was struggling to focus on the spellbook resting in her lap.

“Oooh… Urk! Yaasss… Oomf! Aaah… Glurp!”

The older brunette shuddered in pleasure each time his bulbous tip emerged from her cushiony cleavage to slam into her gaping lips. Great wads of gooey precum jettisoned from Trevor’s swollen balls with every boob-bouncing pump, drowning the matronly Belle’s gargling mouth and painting her pretty face.

They drooled in white sheets down her cheeks and chin, clingy clumps stuck in the glossy hair pillowing her bobbing skull and pooled on the marble around her ears. There was already an unreasonable amount of the sticky seed, yet Trevor didn’t show a hint of tiring.

“Yeah, drink my load, slut! I’ve wanted to fuck you for so long. Watched you prance about in yoga gear for years, showing off your big knockers and bootie.” He growled, and Mrs. Hatcher spasmed through another climax at his commanding tone. Nina felt a slight shiver too. “You’re mine now, understand? My anytime, anywhere cumdumpster neighbor! MINE!!”

“Mhmm… Glooomph~!”

Her eyes were glued shut, jism sparkled like pearls on her lashes, but the affirmative moans and choked gurgles sent a clear message. As did the puddle of flowing pussy juices forming under her round bubble butt.

Nina couldn’t be certain–her attention kept drifting to Trevor’s gob-smacking slab of girthy manmeat–but through the haze of their riotous rutting, she thought Mrs. Hatcher was changing.

Only minor details at first. Crow's feet and frown lines vanished beneath voluminous spurts of spunk as though it were a miracle skin treatment. Stretch marks faded, and sagging flesh firmed up like a timelapse in reverse.

Every swallowed throatful was seemingly redirected to her ballooning bosom, inflating and pumping them up into supersized funbags topped with raspberry nips. Cellulite and fat evaporated, her waistline shrank, and everything about her mature figure seemed to subtly tighten, fine-tuning the curvy housewife into a breathtaking bombshell.

Nina hadn’t realized she was touching herself through the pleated skirt until the initial thigh-clenching warnings reached her befuddled brain. She was fucking soaked, and a wet patch had formed under the press of her fingertips.

“Wha-what? Oh… oh god!” She simpered, jerking her treacherous digits away. The dusty tome had fallen to the carpet face-up, still open to the page of twisting text with the image of the laughing goddess in her feather cloak. “I–I shouldn’t… we couldn’t…”

Nina’s pussy burnt with unfulfilled desire, riding the razor edge. The slightest strum of her little pink clitty would get Nina there, but Trevor was her brother.

Her uber-hung, totally jacked, sex-god twin brother, who handed out bone-melting orgasms like candy canes on Christmas day to lucky bimbo MILFs and blasted them full of his hunky babies.

Wait, was that right?

She scrubbed frustrated fingers through her copper curls, longer and burnished brilliant as rose gold, while the tight schoolgirl uniform pinched her burgeoning breasts and spreading hips as though the clothes were shrinking. Buttons were on the verge of popping across the increasing swell of her perky chest, and girlish nectar slicked her thicker, more shapely thighs.

It was tough to form cohesive thoughts with such a massive breeding fuck-stud, only a fence hop away. Nina’s core roiled with taboo passion. Her toned four-pack belly felt vacuously empty—a void **** to be filled by something huge, stiff, and virile, no matter the source.

“Yeah, hell yeah! Keep sucking it like that, whore. I’ve got another creamy load for you!”

Trevor was cumming again. Blowing more of his bottomless supply of yummy bro-batter straight down Mrs Hatcher’s throat and into… her tits? The same expanding sweater-wreckers that were secured around his mountainous manhood.

Was that right? It had to be. They were enlarging even as she gulped and mashed them around his surging enormity, jolting and straightening in an electrifying climax of her own.

That seemed correct. A loyal, loving fuckslut should cum when her Man did. Nina knew that somehow. It was obvious to her now. Part of the natural order of how things went being ravished by a monster-cocked, beefcake superstud like her twin.

Jesus, she was dripping wet for him.

The tiny red thong was practically sagging like drenched paper towel under the constant deluge of her honey. Just one little flick of her thrumming bean would be enough. Just a brush of her thumb and the sight of her brother’s snatch-splitting fuckstaff…

“Mom, is that you? I’m home!” Called a voice from next door, shocking Nina back to reality like a bucket of cold water. “Are you okay? I thought I heard yelling.”

“Oh no… Oh no, no, no, no!” Nina scrambled in panic, craning her head in the window to spot their neighbor’s daughter, Jessa, entering the home. “This is sooo~ not good!”

Jessa was a year older than her and a star cheerleader at the local college. Precisely the last person Trevor should meet in his magically altered state.

The blonde goddess blew Nina a kiss from the forgotten book at her feet.