John began to freak out. He didn't want to be a girl.
"Stop laughing! This is serious!" said John angrily, as he stamped his dainty foot on the ground.
Mara stopped laughing, but couldn't help but smirk. "Relax. There is another vial in there that will make you male again. Sure you don't want to stay that way? Not even for a little while?" asked Mara.
John shook his head no vigorously. "Okay, come with me. I'll help you find the right vial, " said Mara, as she grabbed his hand and guided him over to the box.
"Oh, pooh, " said Amy. "I always wanted a sister instead of a stupid brother. It would have been nice to have another girl around here for a change. But really, what I have always wanted was a little sister. I just wish that I was the big sister for a change, and you were the little sister. Then you would know what it was like to be bossed around."
Mara felt her body tingling. Puffs of fairy dust drifted to John's hand. His hand tingled, and he tried to shake it off. Mara tried to keep the dust from spreading, and flew away. But the dust cloud grew until it coated both Amy and John.
Amy rapidly grew out of her towel. Her waist became thinner, and her hips grew wider. Large breasts blossomed on her chest. Amy topped off at around 5'9" and looked to be about 20 years old.
John on the other hand rapidly shrank. His clothes hung loosely on his shrinking frame. His small breasts faded into a flat chest. His arms and legs shrank, losing what little muscle definition he had. He stared up at Amy, watching in fear as she seemed to get larger and larger.
Amy squealed in delight and ran to examine herself in the mirror.
"Amy, what have you done?" said Mara.
"Oh, relax, " said Amy, as she continued to examine herself in the mirror. "This is just for a little while. He can always just use the vials later. And I look so pretty now!"
"But Amy, you made a wish! I don't know if the vials can even counteract that. And now that you are an adult, you can't make any more wishes!" said Mara.
"I don't need any more wishes. I look great, and I have everything I want. Fairies are for little girls, so I guess I don't need you anymore," said Amy nonchalantly.
Mara was saddened and a little concerned at how easily Amy had dismissed her. She not only looked like an adult, it appeared she was thinking like one too.
"Can I make a wish?" said a small voice behind them. They both turned and looked at the small girl that John had become. She looked up at them with sad puppy dog eyes.
Amy bent down and pinched his cheeks. "Aww. You are just so cute!" said Amy. "But you don't need any wishes. Your big sister Amy is here to take good care of you from now on. It'll be great! We can share stories, go shopping together, and I can teach you about hair and makeup. It'll be ever so much fun! Much better than it was before. And we don't need any silly fairies messing that up."
Mara was about to protest, but she decided to talk to John first. She flew down to his face and dried his tears. "Don't listen to her, dear. You just wish whatever you want, and I'll do my best to make your heart's desire come true," said Mara.
John was about to make a wish, when a jar suddenly swooped down and scooped up Mara. Amy quickly closed the lid. Mara banged fruitlessly on the jar. Thankfully, it was the same jar John had used earlier and still had air holes.
Amy wagged her finger at the fairy. "No, no, no. Naughty fairy. I am the big girl now. I am the one in charge, and you guys better listen to me. Now what can I do with you? Maybe there is another little girl who could use a fairy...."
Amy saw John fiddling with the box out of the corner of her eye. She carefully placed the jar on the table, and slammed the box shut. She grabbed John, and placed him on her lap.
"Naughty little girl. Those are not for you. They are mine. Maybe when you are older. Or if you are very good. But right now you have been very bad and need to be punished," said Amy, as she swatted him on the behind.
After she finished spanking him, she sent John to his room. Amy grabbed the box in one arm, and the fairy jar in the other, then headed upstairs to her room. She would need to keep them safe if she wanted to keep having fun.