"What is it this time?" sniffed Tony to his brother Mark.
Mark saw similarly skeptical looks on the faces of Tony's friends Jeff, Jack and Eric.
"Jeez" Mark complained. "You guys should cut me some slack, for god's sake. This isn't just going to be a lark"
"Well, what will it be?" asked Tony.
"You'll see. I emailed a bunch of requirements to Jeff yesterday."
Tony, Jack and Eric looked at Jeff who nodded then sat down at the desk in Tony's room and started typing away at the laptop. Mark took up a position near the end of Tony's bed and stripped off his clothes.
"Quite the little exhibitionist" quipped Jack.
"You should talk" laughed Tony. "You're always the first one to rip his clothes off"
"Hey, if you knew how I grew up before I moved here you'd go easy on me. Till I was 8, we lived next to a sort of a hippy commune. I never wore a stitch of clothing after diapers until we moved here"
Tony and Jeff, typing away at the computer, broke into uproarious laughter.
"You're kidding!"
"No way!"
"It's true" laughed Jack. "If you ever saw pictures of me as a little kid, I'm always naked. Always. Don't you remember how I always used to fidget with my clothes my first couple years here?"
"We always figured you had fleas or something"
"No", laughed Jack. "I was just unaccustomed to wearing clothes"
"Well, here we go" Jeff interrupted. He pointed the emitter at slender 13 year old apollo Mark St. Martin. "Last chance to change your mind" he reminded Mark. Mark brushed off the opportunity with a wave of his hand. "Let's go"
Jeff hit enter and Mark felt an electic wave pass through him. First, he started to become taller. Over a period of 10 seconds, Mark became a 15 year old instead of the 13 year old he had been. He moved to stand next to Tony and was just an inch or so shorter now.
Then the second phase of the changes kicked in. Mark felt his shoulders start to lose muscle and narrow. He pressed suddenly smaller hands to his buns. Just as he did so, he felt them almost deflating, becoming less deep but immediately thereafter widening and widening. All over his body, Mark felt himself losing muscle and gaining just a bit of fat under his skin. He turned to Tony's full length closet door mirror just in time to see his short cropped military style hair grow like a time lapse photo of the progress of a weed till it cascaded over his new narrow shoulders. He saw his adam's apple disappear, his jaw become smaller and his lips even fuller as his mouth became smaller. His nose shrank a bit too. On his chest, twin small round breasts formed with great big nipples. Last of all, his thick long penis shrank till just a nub and then a vagina formed. Mark was Marcia.
"Oh my god" laughed Jack. "You're smokin' hot!" Marcia smiled but showed no particular modesty. "I know. I designed me" she said and walked casually out of Tony's room to the room across the hall which was suddenly festooned with stuffed animals and a pink and white color scheme. Marcia returned wearing a 2 piece bikini. She saw her brother's quizzical expression and answered before he could ask. "Jack told me how you and he had traded sex prep courses for each other, playing the girl"
"So . . this is going to be a sex prep course for you?"
"Well, partly" Marcia continued in her new high soft voice. "But it's a lot of other things, too. It's see how girls live. It's see how Mom would've treated another daughter"
"Hey, you agreed with us, you made a promise not to do anything to anyone against their will with the chronivac"
"Well, Tony" Jeff broke in, "It's not as absolutely clear as you and nature boy taking turns being the gash, but he's got a one week time that he's going to be your younger sister. He's going to get different reactions from people but he's not changing anyone else"
Tony mulled this over a few moments but had to agree.
"So, take me to the party your going to tonight with your new girl Claire" said Marcia tapping long nailed fingers on her brother Tony's shoulder and batting her eyelashes at him.
"Save it for someone who doesn't know you had a cock as big as mine a minute ago. And yeah, as long as you're not looking for me to chaperone you or anything"
Marcia wasn't. Tony snuck a look at the profile into which Mark had morphed and saw that Mark had chosen maximum settings on social skills and sexual appetite. Marcia was a cheerleader and sophomore queen bee of the school's social set. He'd also made his "Mark" persona only a bare majority of his mind. When Tony drove over to pick up Claire, Marcia switched to the back seat. "Are you ready for this, Mark?"
Marcia laughed "Mark is in the back seat in more ways than one" Tony had more questions but Claire was at the car now and Tony couldn't ask them in front of her.
The party was a huge affair, a family's mcmansion given over to a few score high school revelers with parents out of town. A state of the art sound system pumped out the moment's hottest tunes for hours. Neither Tony nor Claire were really in their element. They found a relatively quiet spot and kissed, talked and watched. To Tony's amazement, his, until recently brother, effortlessly worked the social whirl, air kissing the right girls and flirting to precisely the right degree with a series of hot boys. Marcia also showed exactly the right disdain for freshmen boys and the less attractive boys and girls. "He's kind of bitch we always hated" Tony remarked to himself. When he and Claire wanted to leave, they tried to Marcia to go with them. Marcia laughed at them over the shoulder of the hunky blond starting forward on the basketball team, her hands in his back pockets.
Tony wasn't sure when Marcia got home that night. He only saw her the next morning at the breakfast table. And that was even more amazing. Marcia deftly worked Tony's parents to eclipse Cindy in their esteem. And she was even more relentless then when playing the 17 year old boys. By the end of french toast and ham plus juice, Cindy was complaining to their mother who simply turned her back on Cindy and walked away. Marcia had a few ingratiating words with her before going upstairs to Tony's room. There she found her older brother lying on his back reading. She closed the door with a chuckle then gave him a soft pat on his package.
"Hey!"
She laughed some more. "It's such a shame that you're such a geek, Tony"
"Hey, you were a geek, too, until a day ago"
"But not as bad as you and you've been your yummy new self for months and months now and, well, look at you, sitting alone in your room reading, what?" She took the paperback in her long-nailed fingers. "The Myth of SisYphus?" Marcia let out a laugh. "You're too much Tony. You've got the absolute best ass in the entire school. Believe me, I know. I had the junior version and I've test driven your nearest competitors. And that face . . " She sighed and ran a hand along Tony's cheekbones. He was a bit creeped out by it all.
"Doesn't it seem a little odd to want me when you're just a female version of a junior version of me? It's like masturbation slightly removed."
She chuckled. "That's pretty good Tony. But let's be quite honest, you want me too, don't you?" Tony looked away and clenched his jaw. She let out a carefree laugh. "I knew it. You like to masturbate too. Hell knows you did enough of it back when your johnson was half as thick as it is now." said Marcia and she smirked at another hard stare from Tony. She sat down next to him and put one hand gently on his shirt so that she could feel his six pack of abs.
"Don't worry Tony. I'm just going to have all the female fun I can for a week. I'm not able to conceive. That's part of my profile, but anyway, you're not my enemy. Cindy and some other people are the only targets I have. In fact, you still want to look out for me, don't you?"
"Yes."
"I know you do, big brother. That's why I squashed something another girl was planning to give a hard time to your Claire. I-"
"What?!"
"You really don't think things like this through, do you? Maybe Mister . . Mal . . raux didn't cover it. You made yourself so gorgeous that every girl out there would like to get her hands on you. So, whichever girl you're with will be hated by other girls. You didn't see that coming?"
"I . . I didn't think about it"
"You're brilliant some ways and just hopeless in others. The ways that you're hopeless make it impossible for you to stop me, so just stay out of my way while I do my thing". With that, Marcia got up off the bed and reached for the door.
"There uh, there is Mark in there somewhere, isn't there?"
"Oh sure, sort of like a fire extinguisher behind glass marked break in case of emergency is stil there"
That day, two different guys showed up at the St. Martin house, at different times looking for Marcia. There was the blond guy from the basketball team and a slender athletic guy with very close cropped hair from the swim team. Tony had to turn both of them away with the news that Marcia was out. Probably with a third guy. On Monday, in school, Tony saw the swim team guy and a black safety from the football team nearly have a fistfight in the hallway preceded by harsh words surrounding the name "Marcia". At home, it had only been 3 days, but, to Tony's amazement, Cindy was in a complete funk inside the St. Martin house, resentful of Marcia's preeminent spot and their mother's heart and powerless to do anything about it.
"Marcia! Marcia! Marcia! That's all you care about" whined Cindy to her mother over dinner. Tony could barely suppress his laughter. Marcia offered a look of sympathy to her mother who gave Cindy nothing for her whining.
Tony saw Marcia afterward. "Okay, some of this I like"
Marcia laughed "How about my doing the black kid? Or the swimmer or the power forward"
"Um-"
"And it's a loose term, because riding on top of blondie was like having two clits. And that flat ass. Ugh"
"Well, then why did you do him?"
"I've got a no fault fucking policy. Besides, I dropped a few hints to him that he's not that . . impressive. Not enough for him to get mad, just enough for him to feel self conscious."
"The swimmer?"
"Oh, I just liked his body. I saw him at the pool. He sort of reminds me of you. Nice shape. Same thing with the black kid. Nice shape body"
"And are you learning anything by this?"
"Everything's not education, you know, Tony. The blond kid was an asshole to my friend Steve's brother. The swimmer gave me a hard time at the Y once. The black kid was an asshole to me when he was in 8th grade and I was in 6th. But, oh, yeah, a guy should sort of roll his hips when he thrusts to get his penis in a girl as far as possible. Also little cocks might not come anywhere near a girl's G spot."
Tony didn't know what to say to that. But in a few more days, Marcia had added a tall redheaded honor society student and the senior class president to her collection. She had Cindy on the verge of tears as the normal course of affairs and the delicate balance among the other queen bees had been disturbed to the point that the girl who was the captain of the cheerleading squad and the girl who was senior class vice president had a full out catfight in the hallway due to a misunderstanding promoted by Marcia.
Her piece de resistance, though, was Saturday when she broke up the senior class couple. When Tony came home, he heard sounds coming from upstairs and through the half opened door of her room, saw the naked backside of a guy pumping away at Marcia with all his might as she slapped his round little ass and said "Give me all of it this time! No, all of it" over and over.
By Sunday, Marcia had cut a swath of revenge a mile wide through school. She stood in Tony's room completely satisfied with her week's accomplishments as she stripped. She saw Jack looking at her. "There's still a few minutes carrot top. And you're still kind of cute" But there weren't a few minutes, not even one. A few moments later, all the same changes took place as 9 days earlier only in reverse. First Marcia lost her vagina and grew a thick healthy penis. The changes cascaded forth until a 15 year old version of Mark stood before them who promptly shrank down to being the real, 13 year old Mark.
"What a bitch you were!" said Tony and they all laughed their agreement.