Brandon took the Gen-X pill to play at being a girl but he bought the cheap street version.  He heard it was unstable but took the chance to save $500. 

Taking the pills, he found himself a thin girl with small breasts, but loved the feeling of being a small woman.  He was playing with his new pussy in the bathroom when his roommate came home early from his trip to New Orleans.  Seeing the horny girl playing with herself, he quietly undressed, and snuck up behind the horny girl.  Brandon was engrossed in his self pleasure, not hearing Greg come up behind him. 

Quickly sliding his cock into the moaning new woman, Greg started thrusting quickly into her pussy.  Brandon screamed in fear at first, but it started feeling good.. to good.  Brandon reached behind himself.. herself.. trying to stop the cock, but only grabbed her own ass to spread for Greg to go deeper.  Holding onto the edge of the tub, Brandon felt his breasts suddenly grow, his thoughts... her thoughts changing... forgetting who she was... Brandie.. That's her name.. cock.. loves the cock in her pussy...

Screaming in pleasure Brandie cums, her now large breasts dripping milk, the last of the male hormones in her body, and the last of the Gen-X leaves her body as she permanently becomes a horny little slut.