You turn up, but Tammy is nowhere to be seen

After a painfully long day at school, having spent most of your time carefully scuffling about in your jeans, you made it to the end of the day. As the final bell rang, you let out a brief sigh of relief at this before realizing that the day was far from over for you. Earlier you'd received detention and were expected to go not just by the faculty but also by a certain someone. You hadn't seen Dana for the rest of the day, and Tammy didn't share your last few classes with you. This left you to go to detention alone. Usually it took place in some empty classroom, so you began to head for the faculty office to see where detention was going to be taking place today.

Slowly shuffling your baskets along the floor, you try to keep your jeans from brushing up to your lips. Despite hating the fact you lacked any underwear underneath, you couldn't help but find the idea of someone accidentally being flashed a bit of your bare cheeks titillating. This had caused some moisture to build up over the course of many brief flashes of panic and arousal throughout the day. If your jeans and pussy were to make contact now, people would either know you're going it rough or think you wet yourself. A less than desirable outcome either way. By the time you had snapped out of your thoughts, you found yourself at the faculty office and looked at the location of today's detention as the last of the students began filtering out of the hallways.

The gym?

That was both confusing and terrifying. Best case scenario, they'd set up a bunch of desks in the gym meaning a lot of students were there, giving Dana that much bigger of an audience. On the other hand, there could be some sort of exercise during detention further increasing the risk you'd flash your ass and/or your crotch. Neither seemed particularly great, but it was either that or have your picture forever branded into this school's history. The choice was easily made. Continuing to drag your feet, you finally reach the entrance to the gym where Dana was waiting, leaning up against a wall, arms crossed.

"Well, well, well, look what the cat dragged in, Miss Panties Donor."

Dana let out a hearty chuckle at her own joke before pushing off of the wall and walking up to you with a confident stride. Standing in front of you, you could feel a slight shiver as her muscular figure dwarfed yours even though she was ever so slightly shorter. Shoulder to shoulder she was pure nerd-punching muscle, with a bosom matching in size, though currently covered by a sports bra underneath a jersey. Goosebumps crawled their way up your body as she sized you up with a malevolent smile, as if she was wondering how to beat you up first. But before you knew it, she stepped back and leaned back against the wall, closer to the door this time.

"Before we go inside, take off your bra. You're already not wearing panties, might as well complete the set."

For a brief moment you consider refusing, but are quickly reminded by yourself about the evidence she holds. Pulling your arms into your t-shirt, you quickly get to work undoing your bra. You'd done this plenty of times before, changing bras without taking off your shirt, and especially now you didn't want to give Dana the satisfaction of flashing her. This seemed to impress her, judging by her expression as you tossed her your bra. She held it up in front of her as you put your arms back into your shirt. Turning it around a bit as if it were some ancient artifact, she remarked "Cute" before stuffing it into her bag. Without saying anything else she entered the gym.

Inside a small group of students were gathered around an older teacher, someone you recognized as Vice Principal Hart. He was an older man, in his late 40s/early 50s but aged gracefully thanks to his earlier career as PE teacher and marine before that. Admittedly you'd always had a small crush on him. Making your way toward the group with Dana, you felt the cold air of the gym hit you, sending a shiver down your spine, but also perking up your nipples. Crossing your arms in front of your chest to cover them, you put your hands under your pits trying to pretend you were warming them up. The crowd was a bit bigger than usual for detention, with roughly 10 students present. None of them Tammy, you noted. Worried this might cause Dana to post the pictures anyway, you sidle up to her and whisper as quietly as you can:

"You won't be posting my picture if Tammy doesn't show right?"

She regards you with a smirk and quietly replies: "I'll see, but if you don't do as I say today, I'll be sure to send a copy to Mr. Hart too." And then she turned to the vice principal as he cleared his throat and explained what would be happening today.

"Evening, students. I'll be running down attendance in a moment, but let me explain what you are here for, first. To encourage some extra-curricular exercise, detention might on any day include some extra PE. You won't be graded but if I notice any of you slacking off, you'll be doing double the exercises next time, or failing to motivate you with that, get suspended. Now, let's see..."

As Mr. Hart began to run down attendance, you feel only slightly at ease. Exercise meant Dana might not be able to mess with you as much but at the same time if you weren't careful you'd end up flashing a lot of students. Eventually he finishes the list by calling out for Tammy. After getting no response, he was about to note her down as absent when Dana calls out to him. "She just had PE so she's in the changing rooms washing up, sir." Mr. Hart nods but tells Dana Tammy should come report in soon. As he dismisses everyone for the first exercise, some simple laps, Dana once again speaks to him.

"Me and Sam had PE today, would it be alright if we changed into our outfits?"

He seems to hesitate for a moment, especially as you look confused by not having had PE today, but he gives a nod so long as you return in 10 minutes tops. With that, Dana pulls you along to the locker room. Once inside you can indeed hear the shower running and Tammy's shaky voice softly humming some sort of song. Confused about where all this is going, Dana leads you to the only stuff still scattered around in the gym, Tammy's clothes and her gym uniform. Dana place her bag down on the bench next tot Tammy's and begins to hoover her plain clothes into them. Once she's done, she looks at you and says:

"Here's your choice, either put on Tammy's uniform and have her go out in my surprise outfit in my bag, or put on the surprise outfit in her stead. I'll give you a hint, it's not going to be much of an outfit."

Before you could even process what Dana had just said, you heard the shower turn off. You'd only have a split second to decide. Not wanting to risk whatever Dana had up her sleeve, you immediately begin to undress, which thanks to today's events doesn't take long. First your shirt comes off and flies right into Dana's grasp who promptly puts it with Tammy's. Slipping on the nerd's jersey, you're quickly confronted by the reality of your choice. Tammy was much smaller than you in height, size and cup size. the jersey struggled to fit your average form as your nipples tried their best to escape from their tight confines. You looked like a complete slut, especially with the amount of sideboob you were now showing off. No time to dally however as you took off your shoes, followed by your jeans which once again disappeared into that dastardly bag.

Now half naked once again, you reached for Tammy's shorts. Before you could grab them, a large cold hand trailed up your butt. Dana's muscular fingers worked their way over your flesh before moving away and coming back down with a deafening and painful spank, leaving a temporary mark. As you stumbled forward from the shock, dropping Tammy's shorts on the floor, a scream other than your painful cry sounded out. Standing in front of you was a still dripping wet Tammy, a towel meagerly held in front of her naked form. It just barely covered her near-flat chest and slit as she clung it to her chest. Seeing her shorts as your feet, she looked at Dana scared and confused.

Tammy, despite being terrible under stress, quickly figured things out and grabbed her shorts to at least somewhat cover herself, slipping them on, leaving you with a naked lower half, doubled forward. Dana smirked at this turn of events.

"Guess both of you will get to enjoy my surprise."