Little Kim is trying out her new rocking horse, dressed in a cure opink top, long socks and of course a diaper. Her diapered butt makes it easy to slide back and forward on the seat, and with her pacifier in her mouth and holding her big stuffed cuddly toy, she's looking like the perfect big baby. After a while though she starts to feel the need to poop.
"Uh oh pony, I think I'm gonna have to go potty!"
But like most little girls, she doesn't really want to stop playing, and since she's got a diaper on, she doesn't have to. She can just do it right there on her rocking horse. She stops rocking, and with her feet on the floor she lifts her butt slightly off the seat. Then with lots of farts and smelly sounding noises, she proceeds to fill her diaper with a lovely big warm poopy load.
She reaches back with her hand to feel the load, but then comes the best bit - sitting back down on the poopy mess and starting to rock again. But then she needs to do more. She takes the weight off her butt again, and starts pushing. She's used up all her farts, but the little grunts and moans betray the secret of what's happening in her diaper - little Kim is messing herself! Then it's back to rocking.
You can hardly begin to imagine how nice it must feel for a dirty little girl to be sitting on her own poop, squishing it all between her legs and over her butt as she rocks back and forwards on her rocking horse. Every time she rocks forwards, the diaper bulges out at the back, and every time she rocks backwards, the diaper goes tight, and the poop is squashed against her butt! The little moans of pleasure tell just how much she is enjoying the feeling. She talks to her pony, telling him how nice it feels, and touching the messy bulge with her hand.
But then she starts to wonder what it must look like inside. She slowly untapes the diaper as she continues to rock, her butt sliding back and forwards on the mess. "It's a very squishy diaper pony!". Then she stops rocking for a moment and undoes the diaper completely, giving us a full view of just how dirty she's been. Then it's back to rocking, but now with the diaper fully open, and her poopy butt slipping and sliding on the mess.
All this is starting to get Kim turned on, and although we can only see from behind, it's to be expected that her smooth pussy has gone all pink and swollen. She's already been a naughty girl by messing herself, but now she needs to be naughty in a different way! She puts her dirty diaper back on and starts rocking faster and faster. She thrusts her messy butt against she seat as hard as she can, all the better to feel the poop inside, and pushes the front of the her diaper against her arms. Eventually she cums and then hangs her head in exhaustion on the back of pony's head.