Mark didn't have to wait long. Almost as soon as his master, Claire, left the room, he felt a mild electric shock. Stretched over the pommel horse set about thigh high with his wrists and ankles tied by red exercise tubing, Mark felt his junior ballet champion buns swelling and widening.
Oh no. She's turning me into a girl, isn't she?
She was. Mark felt his thighs thickening as his legs shortened slightly and his arms did likewise. The combination stretched him straight out over the pommel horse. As this was ocurring, he felt the muscle of his V shaped torso diminishing till he was much weaker. He felt incredible itching at his scalp and then a moment later, his quarter inch long hair was suddenly cascading down across his face. Finally, he felt a tingle at his crotch as his four and a half inch long flaccid penis, lying along the leathery pommel horse surface, shrank to four inches long, then 3, 2, 1, rubbing on the pommel horse then finally receding between Mark's new vaginal lips as Mark let out a high pitched gasp.
"Oooooooooooo!"
Mark strained her neck to see herself in a mirror to her side. She was a perfect copy of Claire only a few years younger. She grunted in frustration at her fate. At least, being transformed into a new body seemed to take away the pain that she had felt a minute ago in her stretched out bowels. Another immediate benefit was that the exercise tubing that bound her had been tied to her slightly larger male wrists of a minute ago. She found that, with effort, she could work herself free.
Just as she finished, into the weight room ran Claire, the physical Claire that Mark knew was really her older brother, Tony.
"Mark?!"
"Yeah, it's me" Mark grumbled in her new feminine voice as she finished untying her ankles.
"And I'm Tony, the real Tony. She-she drugged me after changing me into . . this" said Tony gesturing to her skirt and blouse clad body, the scaled up version of what Mark now was.
They didn't have much time to commiserate, though, for just seconds later, a still naked Claire in Tony's old body came into the room laughing.
"Look at you two losers! Ahahahahahahahahahahahaha!!"
Mark and Tony clenched their little fists in anger.
"Don't worry, if you two hang around long enough, you'll start getting your periods at the same time and I could always program you two for a lesbo thing. Ahahahhahahahahahahahaha!"
The St. Martin sisters glanced at each other and felt even angrier at him for a lesbian thing would've seemed acceptable to both of them, their male minds still enticed by each other's slender hourglass shape. Claire laughed again at their conflicted facial expressions. "Ahahahahahahahahahahaha!"
"Listen, this is the end of the line for you, Claire" declared Tony as she moved a few steps to block the aisle to prevent Claire leaving the room.
Claire laughed. "You don't have to block my way. I could've turned you two into anything I wanted, dogs, cats, a jock for myself, anything. I wanted to give you another chance to save yourselves just for the fun of dominating you both again"
"Come one, girls, let's go". Claire motioned for the two St. Martin girls to bring it on.
"Wait!" said Mark in his 14 year old Claire voice. "You're still Claire somewhere in there. You don't want to hurt us, do you"
Claire laughed. "That part of me is like somebody sitting in the third row of a club wagon van watching someone else drive. Your little ballet dancer's ass was just so enticing to it that I made you into a bitch to not have to deal with it. How do you like your new double width tush? Anyway, I could beat the two of you, easy, even if you still had equipment, Marky"
"Rush him, Mark!" shouted Tony and they both did. Tony tried to attack his old body high while Mark went low. But Claire humiliatingly tossed Tony aside and then slapped Mark's new female ass laughing as she did so. Claire toyed with them. Wrestling one then the other, or both as necessary, and infuriating them with occasional laughter at the weakness of their efforts throwing them aside and easily swatting aside their attempted punches.
The "fight" spilled over into the next room, one with antiquated exercise equipment used by some of the seniors who frequented the Y. Claire had just shoved Tony to one side against a machine that turned a belt around the user's hips such as you might have expected to see on the Lucy show.
"Run that around your big ass, Antoinette" laughed Claire and she then just kicked Mark to one side.
"God, this is too easy. Maybe I should screw one of you while fight the other one" Claire laughed. But Tony saw an opening. His glance met Mark's. Behind Claire was one of those big white sweat box contraptions where only the user's head showed outside of it. The box was wide open and Mark moved into place crouching behind Claire. Tony ran at Claire as fast as she could, putting all the mass of her rump into it, breasts bouncing as she went. "Aaaaaaaaaaaaaaa!"
She hit an overconfident Claire with both hands and pushed her back. Claire tried to just step back to absorb the push, but in her overconfidence hadn't noticed Mark there. She tumbled back and landed on her golden boy ass in the sweat box seat. Mark leaped up and shut the two sides of the box. He grabbed a stray weight stack pin off the floor and jammed it through the latch.
Claire pushed with all the might of her 167 pound athlete's body but couldn't budge the two doors. She groaned and strained and then cursed at the two female St. Martins. She pleaded and begged for them to forget it all, to let her go on being male. When they were completely deaf to her pleas, she shouted at them that she was the real man that she was the dominant one.
She was still in mid rant when Tony found the chronivac powered laptop and finished navigating the menus to change her back to her true self. With the stroke of the 'enter' key, male Claire stopped in mid rant, gasping. Tony and Mark could hear her thrashing around inside the box, almost as though Claire was trying to prevent her body from reverting to female, but finally, they saw her hair grow out and her face reshape.
"I'm sorry. I'm so sorry. I'm so sorry! I didn't want to do those things. I-I couldn't control myself"
Tony turned Mark back into his 14 year old boy self and then himself back into his 16 year old male body.
"There's one lesson to all this" pronounced Tony. "Don't rush Mark at the keyboard"