Lisa was 15 years old, roughly 5 feet tall, had a freckled filled face, some flat, A cup boobs and short, golden hair that reached her ears.
She had that “don’t give a fuck” attitude, and didn’t care about makeup or pretty clothes, she just usually wore an oversized hoodie and some ruined pants. Her roomed was filled with sports and rock posters and the floor was littered with used shirts, panties, cans and chip bags and yet she worked out in that mess, not minding the sweaty smell from it. She did Pushups, minor hand weightlifting and other small exercises, which had made her body slightly muscular, thin and filled with bruises. She wanted to beat her brat brother, Doug, who even at 13 was constantly challenged her strength, and lately it had become more difficult, since Doug had put on some more muscle and weight. Lisa was furious about the idea that Doug would outmatch her, just because he was a boy and had the genetics for it, that he with only minimal workout effort could overwhelm Lisa’s many hours of training and suffering. She secretly wished that she was a boy, having that mass and height a boy could have, and especially one thing made Lisa envious of Doug: his dick. A Freudian frustration that she wouldn’t admit to but made the relationship between her and him even more sour, since she regarded her pussy as a weakness.
She needed to grow stronger than Doug, which made her take all kinds of growth supplement to help her doing so, but none of them seemed to work.
However, something happened one day when Lisa was out running in the woods. Wearing her usual sleeveless sport top, thigh height shorts and running shoes, breaking a serious sweat. Lisa felt a strong tingle sensation in her groin suddenly, but ignored it at first, then it got stronger, making her pussy itchy, so she stopped to check out what was going on, and if she had a rash. She sat down below a tree and looked down into her shorts, seeing her familiar cunt resting on the bottom, steam coming out from it as it was sweaty and smelly just like the rest of her. it was quite hairy since she didn’t bother shaving it since it sprouted out during puberty. She rubbed her lips, and felt there was nothing wrong with it, it was just feeling weird, so she rubbed it some more, making herself feel good and continue doing it, soon she was full on masturbating in her sweaty running cloths in the woods.
As she reached climax, a new thing happened inside her brain, as it released a bunch of growth hormones beside the usual dopamine right as she came. Suddenly Lisa could feel her shorts get tighter, her shoes uncomfortable and shirt stretched out, as she saw her muscles and body expand in a slow burst of growth.
“What the fuck!” Lisa said, as she looked down at her longer legs, who now had gotten thicker too, her hands left her now tight shorts, still sticky with pussy juices as she had made quite a mess in them, and felt the newly grown muscles on her legs, they were definitely bigger than before. She then felt her stomach, her abs where now slightly more visible and harder than before, but as she looked down, she saw her chest was now one cup larger than before. “Holy shit!” whispered Lisa as she fondled her chest “I grew!”
Quickly she went home, kicking off her uncomfortable shoes right as she got into her room. She almost tore off her shorts and top, as she wanted to inspect herself in the mirror right now. She stood naked in front of it, exposing all her scares and marks she had gotten through the years. She watched in awe as the changes was clear to her now, She flexed and felt her parts, her height looked like it had increased half a foot, her arms, abs and legs where bigger, this was a mighty gain done by nothing else but pleasuring herself.
She had to test it out and began masturbating once again to see if it would happen one more time. She didn’t notice before, but her pussy seemed more swollen that last time, it certainly felt more sensitive. As she rubbed herself, she caressed the many scares her body had.