Leah has always been someone who poops and pees more often than average. Her doctor says it has to do with her small size. By the time they get home, Leah can feel that she needs to pee, and hurries off to the bathroom.
"Don't worry about wearing a diaper," Tina calls through the bathroom door. "You clearly don't need one while awake!"
"Okay!" Leah calls back. She's hoping that the weird urge to poop herself earlier was just a one-off. It seems like it was. She didn't have any problems using the bathroom just now.
Leah finishes in the bathroom and puts the diaper back on for some privacy. Then she hurries to her room, where she changes into actual teenager clothes. She then goes into the living room to play on her phone until lunch.
After lunch, Leah continues to mess with her phone in the living room. She's waiting for her post-lunch poop to make its need known. She lets out a small fart, usually a warning sign that she needs to go, but doesn't feel the urge still.
Then it happens. Leah feels something enter the back of her underwear. She gasps. She's pooping! She didn't know she needed to go! But more pressing, she didn't know she was going! Leah jumps off the couch to rush to the bathroom, but finds herself locked in a squat on the floor instead.
Grunts come from her as she slowly, without wanting to, pushes her post-lunch poop into her underwear. Tina hears from the kitchen where she's cleaning up and comes over. She gasps.
"Leah!"
"I didn't know I needed to go until I was going," Leah says between grunts. And when I got up, I got stuck here."
"Well, of course you did. It's difficult to move while pooping." Tina sighs. "All right. I guess you'll be diapered 24/7 until we get this figured out."
Tears spring to Leah's eyes, but she can't disagree. If nothing else, she'd like to stop ruining her clothes!
Out of nowhere, Leah feels herself shift mentally. She's suddenly in the same mental state as she had been when she pooped herself in the store. She feels herself smile as a turd plops into her underwear. Another log begins to crown. Leah pushes it out, enjoying every second of it.
When she finishes, Leah straightens, feeling strangely happy about shitting herself. Then she blinks, and the feeling is gone. She also needs to pee. Leah hurries away to the bathroom, having no issue avoiding wetting herself.
The pattern continues for the rest of the day. Leah sits around in a diaper, completely avoiding wetting herself, but messing herself on accident twice more. Both times, she finds herself enjoying it, and when she's done, not being disgusted for a longer and longer time. The second time, she doesn't realize she's pooping until she smells her mess.
Tina is baffled. She's never heard of this happening before. Having no issue getting to the toilet for pee, but pooping herself consistently? Usually it goes the other way! One thing is for sure, she thinks to herself as she sees Leah to bed in an overnight diaper (just in case). She needs to ask for help. In the morning, she's taking Leah to...