Rachel entered her room with a sigh of relief, and a lengthy fart. She frowned at her ass, waving a hand behind her to try and alleviate the smell; she was slowly getting used to being such a monstrously gassy bubble guts, but she was far from happy about it. Luckily, she hasn't been confronted by her mother yet, but she knew it was only a matter of time; Rachel didn't exactly have many options available to her. Not only would none of her clothes fit, but she now had the extra problem that is incontinence to worry about.
She emptied her bowels in her panties (stretched and stained to hell, but it still held through---she saluted the little soldier for it's service before throwing it away), and emptied her bladder in the shower, but she was now vulnerable; she could poop or pee anytime without warning now, with no real way of preventing it. She needed diapers, but she could just go get them without clothes. She could work through her wardrobe for something to make do (she'll need a wardrobe overhaul anyways, she realizes), but every moment her ass isn't covered is risking her making a mess on the floor.
She briefly felt frustrated at whoever sent the potion, not only leaving it without description but not even bothering to give her things she needs from it's effects. However, out of the corner of her eye, she noticed there was something different about the empty glass. Walking up to it, a little tag was hanging off with a folded note attached. That was strange already, but not the strangest: the tag and note looked...off. The measurements were a little janky, and almost looked like it was written in crayon---like a crayon drawing was lifted off the page and gained another dimension. It felt other worldly, and a little magical.
On the tag was a bunch of scribbles, looking like drawings a toddler would draw when first trying to write letters. She frowned in confusion, staring at the bizarre script until realizing...she could read it. Effortlessly, in fact. Not dwelling too much on the sheer strangeness, she read over the note:
"If you can read this, then congrats! The potion was successful, and you have officially become a big baby! The potion was half-real and half-magic. The real part is a strong laxative, whereas the magic part would only affect those who wanted it to; given that you're reading this, then you truly wanted to be a baby! You might notice that being a big baby makes some things harder, like potty training and reading 'adult' words, but it comes with some added perks. You can now see and interact with the Baby world, something that's always been around you but lost the ability to see when you grew up. Now that you're a baby again, you can see what no adult can see, like this note. In the box will also be a number of things to help you and your caretaker to adjust to your new life, along with further instructions. Enjoy your return to babyhood!"
Rachel read the note, then read it again. It was insane, but...did she really have the right to doubt it? How else could she explain what happened with anything other than magic? In alarm, she moves to a random book on a shelf to read the title, and finds that the letters look unrecognizable at a glance---she had to spend time sounding out each letter, and even then had difficulty putting together that it said 'Math' (must've been an old text book). She feels her cheeks darken upon realizing she really CAN'T read anymore, at least not easily. That means she's not incontinent...she's just not potty trained anymore---technically the same, but it feels significantly more humiliating.
Rachel really should've been panicking more than she was, but mostly just feels relieved that she knows WHY it happened; afterall, can she really deny the claims that she wanted to be a baby when she threw herself at the chance to become incontinent? The only thing she doesn't understand is the weight and the gas. Was the 'big' in 'big baby' literal? She remembered the little note attached to the tag, picking it off and unfolding it. The note was written on the same strange, janky crayon material, and seemed to be a bit less 'official' like a personal note:
"Dear Rachel,
We were confident that the potion would work on you, so we added a little extra something to make you an especially 'big'---and stinky---baby. We hope you and your caretaker enjoy the added perks."
Rachel stared in disbelief, subconsciously grabbing her belly and wobbling it a bit and prompting a chain of squeaky toots; she supposed that explained it. How was she supposed to enjoy these 'perks'? And what did it mean by caretaker? Does it mean her mom? Does Rachel need someone to take care of her now like a baby? She's not so sure she's down for that.
She turns to the box, not sure what to expect. However, as she gets closer, she notes that the bottom of the box looks like a dark void. Looking down, was far bigger on the inside than the outside, breaking the laws of reality. Inside were several different things, all with the same unreal sheen to them. She immediately saw something that she needed at the moment, however, and pulled it out: a thick diaper in her size. She wasted no time in putting it on, more out of panic than fascination.
She gasps in delight when it touches her butt, feeling incredibly soft. She has to lean on her bed to properly diaper herself, fighting with her around her belly and ass to get it properly on, prompting her to have several more nasty farting outbursts. When she sets the final tape, she collapses back onto her bed with a sigh of relief that becomes a burp; now that she was no longer at risk of making a mess, she could truly relax. She allows herself to just lay there, letting the gas bubbles have their way with her (like she has a choice). She feels warm and soft...and stinky.
She eventually sits back up with a satisfied belch, standing from her bed with a loud poot. She walks over to the box to check out what else was inside: there's quite a bit of clothes, mostly onesies and other babyish outfits; one thing of note was a cute onesie dress that almost looked like an adult could wear it. There were numerous baby supplies, with pacifiers, rattles, baby bottles filled with milk, jars of baby food, changing supplies, and the like. There was a book with more of that scribble language on it (Magic Book, it said), and what looked to be a box of crayons. Laying a top it all was a note with descriptions. What should she look at first?