Your older sister, Charlotte

Charlotte stares in shock at the sight before her - cum seeping out from her younger sister's snatch, with an Amazonian futanari standing over her. Charlotte is still in her pyjamas, clearly woken up by your rampage: her tight shorts barely cover her large ass, and her top is cut so short her humongous tits are at risk of peeking out. If Taylor is your flaming hot sister, Charlotte is your centre-of-the-sun hot sister. They actually look very similar to one another, except Charlotte is endowed with even better breasts, a more rounded butt, and waves of platinum hair down to her hips. Add to that her narrow waist, and she looks like the stereotypical bimbo; she may not be a real one yet, but soon she'll be your cum-slut.

"Taylor!" exclaims Charlotte, looking in horror between her siblings. "Who's..."

"Our brother," burbles your sister dopily. "Or... our sister?"

"What? How...?"

Charlotte takes two steps forwards, then freezes as your pheromones begin to invade her system. Her delicate nose sniffs curiously, before she suddenly inhales deeply, her shoulders and mountainous chest rising. "Ohhhhhh..." she sighs, as you stride towards her.

"I want to fuck you, big sis," you say softly, tilting her chin up to look at you. "You're just too hot for your own good. I was gentle with Taylor, but with you... I can't hold back."

Charlotte hesitates, trying to resist, but it's a futile attempt. Panting with desire, she presses herself against you, sucking your giant balls as she caresses your round ass and rubs your labia. As you look down at her, standing between your legs, her head only reaching your belly button when she straightens, you register with surprise just how tall you've grown. Then that flicker is gone, obliterated by the all-consuming fire of your lust. Seizing her, you flip her onto her front, her collarbone resting on a low chair whilst her straight legs raise her butt high in the air. She wiggles it for you, your pheromones washing away all her inhibitions. You kneel to reach the right height, seize her hips, your hands - which have grown in proportion to the rest of you - almost touching one another; and you plunge in.

Your older sister screams at your entrance, clutching the chair legs desperately as she begins to sob with the pain. However, as your cum-coated shaft forces its way inside her, the potent chemicals begin to take effect, healing her ruined pussy into one that will stretch to your colossal size. As you bump against her cervix, Charlotte's sobs turn into erotic gasps and moans, reaching to fondle her left tit with one hand. As if on cue, a dazed Taylor wraps herself around your back, fondling your giant bosom as she humps against your firm ass. The tingling pleasure in your chest only pushes you further, and you drive the rest of your cock right into Taylor, uniting her vagina and uterus as you distort her abdomen.

Charlotte's shaking, but whether from pleasure, pain, anticipation, or all three, you don't care. All you want to do is fuck her tight bimbo body, to satisfy the urges of your cock. You jackhammer into her perfectly positioned body, forcing Charlotte's legs as wide as they will go as your gargantuan sword plunges rapidly into her body. She starts writhing, her limbs jumping every time you sink to the hilt, her mouth letting out a continuous unintelligible sound of ecstasy. The glorious stimulation of your cock is only distracted from by a quite pleasurable sensation from your comparatively inexperienced pussy. You look down, lifting your heavy testes to find Taylor greedily fisting your cunt, suckling on your clitoris as she does so. It's certainly enjoyable, but your mind has only one priority: to fuck. Earlier, you might tolerate being fucked yourself whilst you fuck someone else, but since then your appetite has grown. Now the beautiful woman squirming as your cock thrusts all the way to her chest is only mildly satisfying; you need more.

Grasping Taylor's athletic torso with one hand, you throw her atop her older sister, who's far too overstimulated to notice. As Taylor spins to face you, eagerly licking and stroking the top of your huge shaft each time it emerges from Charlotte's ruined pussy. As you stare at her pretty face lustfully, you feel a tingling in your groin, at a spot just above your dick. Even you are surprised as the skin begins to distort, as a second penis begins to grow above the first. Another consequence of Cassy's throwaway command, for your body 'to adapt to your every desire'. Your new penis rapidly inflates, and within seconds it reaches six inches and bumps against your sister's chin. Taylor's eyes go wide as she catches sight of it, before she grins like a Cheshire cat, and opens her mouth wide.

You spare a hand to guide it in, and with each thrust your growing cock enters deeper into the blonde's mouth. Soon you feel your anaconda filling Taylor's throat, but she doesn't even ****, just stroking your shafts and gazing at you lustfully. You grow inside her, causing her throat to thicken as you push into her chest, all the way to her stomach. You toss your lustrous hair back as you groan at the feeling of two huge cocks skewering your sisters, and feel a sudden surge in growth. You hear the popping of bone and tearing of muscle as Charlotte's hips and Taylor's jaw dislocate, shortly followed by the cracking of Taylor's collar bone as it is **** to accommodate your absurd girth.

This is what you wanted, even if you didn't know it. Both sisters lying front to back, as your two cocks pound them like twin jackhammers, Taylor's eyes rolling and Charlotte's body twitching as the stimulation they receive transcends that of orgasms, ascending to pure mindless bliss. Your shafts start bumping the opposite ends of their bodies, and finally it's enough. You feel a great surging within your body, and blast into your sisters.

Both girls writhe and shake on their skewers as hot cum fills every space in their body, causing their bellies to bulge like balloons. White fluid ejects from Taylor's pussy and arsehole like they're fire hoses, and gushes between Charlotte's ruby lips and from her elegant nose. Where the base of your cock is jammed, impossibly wide, into their bodies, the semen is put under pressure, fizzing out of both of Charlotte's distorted holes. For Taylor, it spurts from her mouth, nose, and ears, much of it landing on your grapefruit-sized balls. You stare with wild exhilaration as your cum even starts to drip from her eyes.

You pull out, with a grunt of satisfaction, squeezing your big breasts together as your sisters crumple into a thick puddle of gunk. After that experience, they will be capable of nothing but fucking.