Side note: This story isn't "me if I were to be a girl", it's just a name I chose :).
Katie slapped an ice cold soda in Timmy's hand. He had been thirsty ever since he left his house to hang out with his friend. Timmy snapped open the can and a light froth rose from the can. Timmy chugged the can down and smashed it, "That was refreshing!" He threw the can away. "Come on, Timmy." Katie gestured. "Let's go to the park!" They walked outside and just talked about their lives, stuff at school and such. It seemed like they were on a date, but really, they were just great friends. Timmy's stomach growled and churned. "Ugh..." Katie turned to him, "What's wrong?" Timmy shook his hand, "It's nothing, I probably just have to burp. I did down that soda pretty fast." He chuckled. Timmy stood up and continued walking. A few minutes later, Timmy fell to the ground, holding his stomach. "Oh God..." Katie went over to his side and rubbed his back. "Hey... Timmy?" She spoke. "Yea?" "You know that soda I gave you?" Timmy looked at her. "Yea...?" "Well..." She began. "Well? What's 'Well'?" Timmy started to get scared. "That soda was from my dad's experiment cabinet. It was a gender soda." Timmy cringed as the words entered his ears.
Timmy's body began to grow sore. "Try not to fight it, Tim, just keep drinking the soda." She rubbed his back. Timmy took the can and sipped the soda. He felt a sharp pain in his back. Katie stood back and Timmy's bones were beginning to crack as he slowly got shorter. He arched back in pain, screaming for he could feel his spine shift itself into a more feminine composition. Panting from screaming, he could feel his skin crawl, turning softer and giving his skin a creamier tone. Timmy took another sip. His hair quickly grew down to his shoulders and his face grew fuzzy and warm as it morphed into that of a girl's. "Katie..." He managed to utter in a slightly higher voice. His shoulders looked as if they were being sanded down, becoming rounder and less broad. His collar bone dipped and split into a feminine neckline. While he had the time, Timmy tilted his head back and let some more soda flow down his mouth. As he put the soda down, he noticed that his hands were changing. His nails slowly grew out as his hand and his entire arm became slender. He could see the same with his legs. His stomach pulled into itself and his waist caved in with a loud *SNAP!*. Bending down to comfort the pain on his waist, he could see that his pants had slipped off of him. He looked up and blushed at the fact that Katie was staring at him half-naked.
He chugged the rest of the soda down and threw the can to the curb. When he did, Timmy could feel his privates begin to shift and change. He squirmed, feeling his penis recede into his body. His balls shot up into him, making him jump. The remnants of his penis were slowly morphed into a vagina. Just when he thought everything was over, Timmy's chest started to expand. A pressure was building up behind his chest, pushing out more and more. The pain was unbearable! After suffering, what was an hour to him, he had sprouted a pair of breasts.
Tasha stood there, surprised but upset with Katie. She looked up at Katie. "Uh... Do I know you?" She jokingly said. "You..." Tasha angrily walked over to her. "You did this to me!" She gestured to her new feminine body. Katie examined her, "Yea..." She said in sarcastic disappointment. "Really, Katie, you should tell me these things before you just hand them out to me, next time!" Tasha sounded a bit whiny. "You're right, I'm sorry. I should have told you. But on the bright side, if you want to stay like that, you just have to drink another soda. The effects wear off after a day." "You owe me, Katie." Tasha placed her hands on her hips. "Ok, what do I owe ya?" Tasha went up to her and kissed her. "A date." Katie giggled, "Alright, I'll go with you!" Tasha went over to pick her pants up and they began to walk back to Katie's house to get some new clothes to fit Tasha's new appearance. "So..." Tasha said, "You said something about another soda?