It's Jim's 13th birthday today, his parents leave him with his sister for 3 weeks every July 1. Which means they miss Jim's birthday on the 3rd. Jim is an average boy in every way. He is about 5'2, 115 lbs, has brown hair, and get's B's and C's in school. Jim's sister is named Kate, she is 15, has brown hair the same shade as Jim's, 5'5, 100 lbs, and has A cup breast. Kate and Jim are best friends so Kate decided to get him something really cool for his birthday, Kate went down the street from their penthouse to a new magic shop. When she walked in she asked the old lady for something fun for a birthday present, the old lady handed her a box she said was full of magic soda, she said it would never run out and would really make a good gift.
"How much?" Kate asked.
"$20," the lady said. Kate handed her the money and left.
On the day of his birthday Jim walked down the hall to the kitchen to find Kate sitting at the table in an over sized t-shirt and panties, you could tell she wasn't wearing a bra but it didn't matter because she had little boobs. In front of Kate was a box with a bow on it.
"Happy birthday Jim!" Kate said handing Jim the box.
"What is it?" Jim asked.
"Magic soda," Kate said. Jim opened the box and saw more soda cans than he thought could fit in a box that sized, Jim pulled one out.
"What does T.G. mean?" he asked.
"I don't know try some," Kate answered. Jim opened the can and drank some he didn't really know what it tasted like but it was good. Suddenly Jim's body was covered in light and when the light stopped Jim looked like a younger version of Kate. Jim is now 5'3, 90 lbs, needs a training bra, has hair just like Kate's, and despite Jim's weight had a nice ass like Kate, all of Jim's clothes stayed the same.
"What the hell happened to me?" Jim yelled looking in her pants at her vagina, "Why am I a girl?" she asked.
"What part of magic soda don't you understand?" Kate asked.
"You drink one now," Jim said feeling her really small right breast. Kate reached in and pulled one out.
"I wander what B.E. stands for," Kate said. Kate drank some and felt a tingling sensation in her body as her breast grew from and A cup to a B cup. When Kate saw what happened she started chugging the stuff. She felt the same tingle then her boobs grew to E cups. Jim grabbed the soda and started drinking until she reached D cups.