Zoe was waiting for her brother outside of the gym. Ever since classes started this morning, girls had been whispering and passing notes to her, begging for sex. She knew this had something to do with his stupid stone, and she intended to force him to fix it by any means possible.
Jon stepped out of the gym, looking uncomfortable and distracted. Zoe grabbed the collar of his shirt and pulled him aside.
"Jon!" she said in a stern whisper, "Your stupid fucking stone is making my life hell! I want you to fix this RIGHT NOW!"
She had barely gotten the words out when a funny feeling came over her. Somehow, she had never noticed how hot her brother was. She had a sudden, overwhelming urge to beg him to have sex with her, and the thought of it was making her feel nauseated. How could she want to have sex with her brother? Eww!
Jon was bewildered, but also worried - when Zoe had grabbed his collar, it had pulled his shirt up, and he was worried that it would expose his interminable erection. He pulled his shirt down hastily, and said "I don't know what you're talking about, Zoe!". Her reached into his pocket to make sure that his 'equipment' was still hidden.
Zoe thought Jon was reaching to protect the stone. She pulled his hand out of his pocket and reached inside. Sure enough, there was a small, round, hard object in there. There was something else hard in there, too, and Zoe knew exactly what it was. She started to feel a moist warmth between her legs, and the nausea increased. Jon's eyes widened in horror as he realized that, if his wish affected teachers, then it would affect his sister too!
Zoe said "I wish that I didn't want to have sex with you, you pervert!"
The stone glowed... it still couldn't undo Jon's wish, but it could find a way to make Zoe's wish come true anyways.