"Hmmmm..." Melanie still looked at herself in in the mirror flexing the muscles of her stolen body, "this isn't enough" she thought, wanting to make more modifications to herself, or her brother's body technically.
As she was fully in control over the body she began to produce more male hormones that fluctuated trough all of herself, changing instantly. Her muscles grew, feeling and looking how her arms, legs and torso got toned, looking even more muscular and mature. Her height elevated until she was almost 6 and a half foot tall, making her clothes rip a little, her hair grew quickly too, her chest was decorated by many black hairs matching Jeff's, speaking of him, as the hair of his head acted like Melanie's pubic hair, a hair trail was drawn on her belly, connecting Jeff's hair and her belly button. The "younger sister" was now satisfied with her new form.
Melanie had the head of a 18 years old looking blonde girl even that she was just 15, but with the strong, hairy and sexy body of a man in his thirties, while still having Jeff's head glued her crotch as her pussy. She could qualify for a gay porn actor if you ignored her head and crotch.
Melanie smiled in excitement, she lifted her shirt to see her masculine and fabulous toned male chest, she lowered a little her pants and underwear to notice the hair trail on her belly started from Jeff's head, still vibrating with the two toys stuffed inside him.
"You should thank me big bro~ Not everyone has this massive body!" She said flexing her muscles in many poses, feeling powerful and amazing.
Melanie then removed her torn clothes damaged by the transformation, except for her underwear that somehow was intact but awfully wet thanks to Jeff, Melanie giggled and moaned looking at it. She didn't know if she should be considered a man or a woman, she considered herself as female but didn't care about that but caring about her pretty face, masculine body and sensitive human vagina.
Then she went to her parent's room, deciding to borrow some of their dad's sportswear, looking her sexy self again in the bathroom while also noticing the big vibrating bulge on her crotch, things were just getting better for her, for Jeff... Not so much.