Jen heard that her brother, Tom, had just come home and went straight to his room. She pulled on her mom's molaton pants and went to her brother's room, entering without knocking on the door and closing it.
"What are you doing here Jen? You know I don't like you coming into my room uninvited." Tom said. Jen knew that Tom didn't want her to go into his room because he is gay and believes that no one in the family knows, but she has known since she saw him watching gay porn without him noticing.
"I just want to spend some time with my brother. Or do you think this is a problem?" Jen said grabbing him by the arm, purposely pressing it against her breasts so he could see she wasn't wearing a bra.
"Let go of me, don't hold on to me like that." Tom said making her release his arm.
"Didn't you like being hugged by your sister?" Jen asked pretending to doubt, then smiled and said "I know why you don't want to be with me, it's because you're gay, aren't you."
Tom went white with the scare, he didn't expect her to know his secret. Then he blushed and said "How do you know that? I was sure I was hiding it very well."
"This is not important. But I have something new that I want to use on you and I'm sure you will like it." Jen said
"And what would it be?" Tom asked
"This is it." Jen said taking her brother's hand and taking it to her hard cock, making him feel it.
"No way. That's not what I'm thinking, is it?" Tom said
"That's right, your beloved sister has grown a dick and she wants to use it to fuck you." Jen said. Tom didn't say anything else, but she could tell he was interested. He then undressed and turned his back to Jen offering his ass.
"I don't know if I will be good enough but I will do my best, this is my first time having sex with a girl." Tom said
"You should say that before you fuck a girl and not before you get fucked by one." Jen said in the middle of a few laughs and took off her clothes.
Before placing her cock inside her brother's ass, she compared the size of hers with his and confirmed that his was a little bigger, with 5 inches, and then finally started to fuck his ass. Tom's ass was tighter than she expected, but soon she got used
to it. She could tell by the look on his face that he was enjoying it.
Soon Jen felt that feeling that was becoming familiar to her said "It's almost out, I'm going to come."
"Go with everything you have." Tom said and Jen gave one last push and came in his ass.. Tom also came when he felt his sister's hot cum inside him.
When the orgasms ended the two sat looking at each other, until Tom felt a strange sensation in his balls and put his hands there, discovering that his testicles were no longer in his ballsack, which was empty now.
"How did this happen? My balls are gone." Tom said
"What? Let me see." Jen said and looked closely as the wrinkled skin of her brother's empty scrotum became smooth skin, then a line appeared and a vagina opened in its place. She got excited again to see her brother's bag turn into a vagina just under his dick, her dick got hard again and she started to stroke it. Suddenly she realized that Tom's dick had started to shrink, she also realized that her dick was getting bigger.
Tom, seeing his sister stroke her dick, made her sit up and leaned over to suck her growing cock while stroking his own shrinking member. Soon his cock had become a clitoris and he continued to suck the member between Jen's legs, which was now 9 inches.
Jen pinned Tom up, making him fall flat on the floor, and sat on his head so that all her brother could do was lick her balls. He tried to grab her cock, but she wouldn't let him, so he reached for her ass and put a finger in her ass, finding her new prostate.
The new stimulus made Jem bend forward. In this new position she raised a little and pushed her cock down, presenting its tip to Tom's mouth and promptly put it inside. She didn't stay put and put two fingers inside her brother's new pussy and started licking his clit. Soon Tom had an orgasm, which made him stimulate Jen in a more erratic way, which made her come too.
"That was incredible. Who knew my dick would get bigger, it got really big." Jen said while watching her dick go limp
"And me? I lost my dick." Tom said
"Do you miss if?" Jen asked
"No way, I loved it." Tom said
"Do you want me to fuck you there? I can do this with great pleasure." Jen asked
"I would love to, but I will have to decline the offer." Tom said, got up and started dressing "I have to show this to my boyfriend, he will love it." he said and, having finished dressing, he left.
Jen then..