She starts to feel horny and masturbates.

Still holding her dick in her hand she felt a deep and hot lust fall over her once again. Her heart rate accelerated as she thought about fucking Josh with her huge dick. With each passing second more and more blood was **** into her penis, slow erecting it to its full stature. Her cock stretched all the way past her abs and up to her nearly flat chest. Having to use both of her hands now, she violently masturbated, her mind in two places. Part of her was completely engrossed with pleasuring herself and her colossal cock, and the other was loathing as the harder she masturbated, the more she thought about the flatness of her chest. The now familiar feeling of her orgasm was now upon her, each time her cock spasmed a wave of ecstasy slammed into her body, and with each spasm her cock bulged as it ejected large wads of cum from her heavy balls all over her chest and torso. Her nearly painful orgasm lasted minutes she was drenched in her own thick solid white cum. In the afterglow of her most powerful orgasm yet she massaged her cum soaked breasts praying that somehow they would see some growth like her height and cock had. Just when she was about to give up hope of her breasts growing anymore, she felt lightheaded once again.

The lightheadedness was soon followed by a tight and full feeling in her small breasts. Her breasts felt hot and became extremely sensitive causing her to massage faster and harder. Kneading her tits they began to expand slowly. Minutes went by while her breasts grew bigger and bigger giving her hands more and more tanned tit flesh to knead. After more than an hour, the heat in her tits subsided and she became lucid again.

Her tits were huge. Still just as perky as they'd been while A cups, but now they were much bigger. She got up and walked to her computer wanting to know how to measure her tits properly but couldn't help but massage her tits with her left hand as she searched the web, her tits almost perfect spheres and far beyond handfuls. Getting out a measuring tape, she wrapped it first around her incredibly thin torso then around her gravity defying tits. Writing down her measurements on paper then cross referencing the site she found online, she realized she would need a 25K cup bra...