You can see a girl peeking through the crack of the open door. She's a thin, pale skinned redhead with along, silky ponytail. You've seen this girl around campus, and her name is Robin. She's usually very funny and cheerful, and she's known for the occasional prank she pulls on her closest friends. It's kind of her thing
Everything about this situation screamed "prank", and based on the fact that her eyes land directly on you upon quickly scanning the room further backs up that theory. Robin quickly glances at Bethany, confirming she's still showering, then, with a swift motion, grabs you from the top of the clothes pile and plunges you into the darkness of the dorm room hallway. She moves her free hand towards you and you can see she has some sort of container in it. A small, plastic vibrant red bottle with the tag "Itching powder" enters your field of vision.
This isn't part of the plan. This girl you hadn't accounted for just showed up out of nowhere and is now going to put itching powder on you. This isn't good. But you can't just transform into a human and freak Robin out, blowing your cover at the same time. You have no other option but to roll with it. You can only watch as Robin carefully kneels down on one leg and places you on her other thigh, opening you up. The way you transformed makes it so your face constitutes the back side of Bethany's underwear. Robin puts on a rubber glove and dabs the tip of her index finger with the open bottle. She then carefully rubs it in a vertical line along the middle of your face.
You expect your skin to start itching, but since you're just a piece of cloth, you can't really itch. However, you do feel Robin's finger running down from your forhead to your chin. Before you know it, the girl has gotten up and you're in her hand again, being carried back into the bathroom. She quietly opens thedoor just a bit and extends her arm to put you back on the clothes pile, as close to the position you were in before as possible. She then closes the door and, shortly after, the shower Bethany os taking comes to an end.
What is now a wet, smooth glistening version of the giant girl comes out of the bathtub, dripping water from her hair, elbows and ears. She quickly picks up a towel from the rack and starts drying off. You watch in awe as the 15x25 inch piece of fabric explores every square inch of Bethany's skin, as she dries off. You think to yourself that transforming into a towel next time might not be a bad idea at all. After she's dry, she finishes getting her hair done with a blowdryer and then turns to you.
This is the moment you've been waiting for. The worries about having itching powder on your backside disipates as thrill of being seconds away from being worn takes over. Without giving it much thought, the girl unceremoniously picks you up by the waistband and gives you two small stretches while she brings you down to her ankles. You look up and admire her magnificent legs as she lifts one up to put her foot through your hole, and then the other. Once you're in place, she starts pulling up. You feel your face stretch to the sides as her powerful thighs start to widen. Right before you meet her crack, the inner sides of your leg holes touch the lower part of her butt cheeks, and she stops pulling.
She then pulls up your front and you can feel the rest of your body come in contact with her crotch. One final unexpected tug plunges your face deep into her ass, enveloping you in darkness and just the slightest humidity. Everything that happens from this point forward is unclear to you, but you can more or less deduct what's going on based on her movements. You manage to figure out at one point that she's done getting dressed, since not only do you feel her tights pressing against the outside of your new panty form, but you can tell she's walking around by the way her cheeks gently smush you from the sides with every steps she takes.
You've never been this close to a girl, especially one that's unaware of your whereabouts. Sure, you've had your intimate moments with girls, but this is different. It's much more personal, and you're loving it. The feeling of being used as underwear is much more amazing than you would've imagined. At least for now. You can't see anything, since you're wedged between two massive mounds of flesh, but the smell isn't bad at all, since Bethany just showered.
However, things turn for the worse the second the itching powder kicks in. Since Robin hadn't put a lot of it on you, it wasn't that noticeable, but shortly after getting ready for class, Bethany starts noticing a slight itch inside her rear, just annoying enough for it to need a scratch. She cups her hand on her butt and sticks her index and middle finger into it, scratching herself in small circles. For her, this was just a small scratch. For you, however, it was much worse. Suddenly, you feel a giant fingertip push on the back of your head. You plummit deeper into her crack while she vigorously rubs you against her puckered sphincter. By doing this, she's not only rubbing you against her anus, but also rubbing the powder firther into her skin.
This isn't good. Not only does it stink now but she's made it worse without even realising. Bethany gets a moment of relief after scratching herself while she picks up her bag and heads towards the door. She gets one more scratch in before leaving, forcing you to relieve her asshole from the itch again, before opening the door to the main hallway.
Does Bethany relate the itching to a possible problem with her underwear before leaving? Or does she think it's just a random itch and decides to continue with her day, still wearing you?