Jenny initially thought about being mounted by a horse, but decided it would be better not to do it with a complete animal. She then thought of a centaur, but even though she had altered the perception of reality so that no one would be surprised when they saw her, she was still the only centaur in the world at the moment. The only solution to this was to use Chronivac to transform someone, with the only question being, "who?". It was at this time that the front door of the house opened, Jeff's mother and little sister had arrived home earlier than expected.
The footsteps approached and the bedroom door opened, Jeff's mother, Norma, was holding his sister, Katlyn, by the ear.
"Hi Jenny, I didn't know you were here at the house." Norma said
"I came for a visit." Jenny said
"And where's Jeff? Did he leave you alone?" Norma asked
"He left to take care of a quick matter and will be right back." Jenny said
"Good. I know how difficult it is for you to go up and down stairs as a centaur, we are sorry for not having a more appropriate structure for you in our house." Norma said
"Jeff said you guys went shopping. I thought you guys would take longer to get back." Jenny said
"And we were going, but Katlyn here threw a tantrum and I couldn't do the shopping. I'm going out shopping again, this time alone, and she's going to be grounded in her room in the meantime." Norma said
"That's not fair mom. You promised you would buy me that doll." Katlyn complained
"I said I would buy it if you studied and did well on your exams, but instead you just messed around with your friends and your grades were disappointing." Norma said to her daughter and then turned to Jenny "I'm sorry to ask this of you, but could you and Jeff keep an eye on Katlyn to make sure she doesn't leave her room?"
With an idea coming to mind and seeing that Norma and Katlyn's profiles were now also present on Chronivac, Jenny agreed.
As soon as Katlyn entered her room and Norma left again, Jenny positioned herself in front of Chronivac and edited Katlyn's profile, making her go from Jeff's younger sister to Jeff's twin sister, so she would be the same age as her brother. For this change she activated the reality alteration and only she and Jeff would be aware. She also already had some friendship with Katlyn and added that they now studied together and were very good friends.
When saving the changes, Jenny confirmed the changes based on the photos Jeff had of her sister, which had been altered and showed her actually older. At this time she made a new change, and to increase the fun, she changed Katlyn's race to centaur, with her equine part being male, and making this change without reality alteration.
It wasn't long before a loud creaking sound, and then heavy hooves, were heard coming from the next room, then seconds later came a scream from Katlyn. Jenny went there to see the result for herself.
As soon as she saw Jenny open the door to her room, Katlyn made a quick movement and lost her balance, falling into a position where her sheath and balls were perfectly visible. (Her equine part was covered in white fur and her tail was the color of her hair) She then futilely tried to cover and hide the horse body that was now the lower half of her body. "Please don't look." she said
"Why not? You look great as a centaur. Now we are equal. We've been friends for so long, I'm sure you've imagined yourself being just like me." Jenny said
"I already imagined it and I don't think it's bad that I suddenly became a centaur, but..." Katlyn said and looked down between her back legs, where her cock was sticking out of her sheath and getting hard "Please no, I can't have a dick, I'm not a guy."
"I like that. It's exactly what I needed." Jenny said, not disguising her intention at all
"You what? No way, I'm not going to fuck you and you know there are several reasons for that. First of all, I'm a girl and I'm not going to be the one fucking. And you already have my brother, I don't want you to cheat on him, much less am I willing to collaborate with that." Katlyn said, her body saying otherwise as her cock reached full erection.
"I know you're into it, and let's be honest, as girls you know I have needs too. I love Jeff, but neither he nor anyone else would be able to fully satisfy, at least not until now. At the moment only you can. Don't worry about Jeff, I won't keep it a secret from him and I'm sure he'll understand." Jenny said
Katlyn heard everything, knowing that the temptation was great, but she still tried to resist.