Everything. Growth. Muscle Growth. Breast Expansion.

Sarah slowly straightened herself, still on her knees, and Adam could see the effects that the pills have had on his sister's body. It was entirely transformed. Her whole statue was broader, thicker, less fragile, more muscular. As if she had done intensive bodybuilding over a longer period of time. It looked like she had even gained a few inches of additional height. She arched her back, further pronouncing her swollen big and round tits, which sat high on her muscular chest, crowned by erect nipples. Below, her belly was still bloated, full of her brother's "Growth X" overdosed cum. And even further below, Sarah fingered her pussy and rubbed over what looked to be her engorged clit. It had grown in length and stood out at two inches. She had her eyes closed, oblivious to her surroundings and was moaning. Her arms bulged with muscle as her hands focused on moving inside her pussy and over her engorged clit.

Adam watched with fascination and arousal at the sight of his amazon turned sister pleasuring herself, and it didn't take long for his huge eleven inch cock to jump to full mast. It immediately started to leak precum and to spread it's intoxicating scent. Adam's Growth X overdosed body and mind knew no caution, only arousal and pleasure. And while he watched his transformed sister pleasuring herself, he started to stroke his lengthy shaft, producing more and more precum. Sarah immediately caught the familiar scent and her eyelids shot open. Both siblings eyes met for a second, before her gaze was drawn downwards and focused on her brother's cock. She licked her lips, and continued with her masturbation. Her eyes remained fixed on her brother's sizable member, but her moans intensified and the motions of her hand's increased in frequency and speed.

To Adam it looked like his sister was still under his spell, and already Adam imagined the sight of this muscular and powerful amazon, yet powerless in the presence of his glorious fuckstick, on her knees and servicing him like any true slut should.

Sarah had started to masturbate by moving two fingers inside her pussy, but that didn't seem enough. Not after the rough fucking she had received by her brother, not after his thick shaft had stretched her pussy beyond any previous limitation. Soon she increased the numbers of fingers. First a third, then a forth. And soon she was plunging her whole hand inside her cunt. She further sped up her motions, fisting herself, moaning in pleasure and ecstasy, so close to orgasm. Just waiting for that tiny bit extra that would put her over the edge, waiting for the release that was about to come. But it didn't.

Instead, what happened next was beyond anyone's wildest imaginations. Instead, the transformation of her body continued. She continued to grow in height, and at the same time her body mass expanded further. Broad, muscular shoulders. Powerful arms, bulging with definition and strength. Her calves and thighs thick and beefed up.

Sarah stood up, no longer on her knees, but continued to fist herself, even intensified her efforts. Anticipating, waiting, longing for a release that just wouldn't come. Just as she thought that she would finally reach a new high, instead her alteration continued. She arched her back, and her already big and swollen breasts expanded further. Masses of bountiful tit-flesh appeared, increasing her overly large bust further, and her her nipples swelled as well.

After what seemed like an eternity watching in slow motion, Adam could see the end result: Voluminous and massive knockers, the size of volleyballs or bigger, standing firm and proud, crowned by incredibly big and thick erect nipples.