When you were a very little baby, Mommy and Daddy took care of you. They fed you. They dressed you. They carried you everywhere. 
And they helped you use the potty! You were much too little for diapers. If you used diapers like Mommy and Daddy, you might have gotten sick. So whenever you needed to go pee-pee, or poo-poo, they would hold you over the potty until your messes needed to come out. 
Now you are big. You can walk, and talk, and feed yourself. You can even tell Mommy or Daddy when you need to use the potty. Mommy and Daddy are so pleased and proud of you!
Lucy is a little bunny about your age. Lucy wears undies and uses the potty. Do you wear undies and use the potty, too?
One day, Lucy sees a big box. Mommy opens it for her. Inside are a bunch of funny white things that look like undies, but they’re too big and thick! “These are called diapers, Lucy,” Mommy says. “You’re getting big enough to wear and use diapers like Mommy and Daddy now! When you’re a bit bigger, they’re where you’ll go pee-pee and poopy instead of in the potty.” Lucy isn’t sure how much she likes that idea! She likes wearing her undies just fine. “That’s okay, Lucy. You’ll learn when you’re ready,” says Mommy.
After a while, Lucy notices something. Mommy and Daddy never use the potty. When they need to go pee-pee, or poo-poo, they just go in their diapers! And then they change each other’s diapers in the bedroom. Lucy still likes her undies, but she still wonders what that must be like.
One day, something amazing happens! While Lucy is playing, something warm and wet starts to come out all by itself. Lucy is going pee in her undies! She really likes the warm wet feeling all over her pants. She runs to go show Daddy. “That’s called having an accident, Lucy. Accidents are when our pee or poop come out when we aren’t wearing a diaper.”
Lucy loves having accidents!
Another day, just after lunch, Lucy feels something move under her tummy. She goes to hide behind the couch, squats, and pushes. She doesn’t know why; her body is just telling her that’s a good thing to do. Something warm, squishy, and very, very stinky comes out of her bottom and fills up her undies! Lucy is having a poopy accident! Mommy and Daddy are so proud of her! Having lots of accidents is an important part of learning how to use our diapers!
Lucy keeps having lots and lots of accidents! Mommy and Daddy always give her plenty to drink, and special foods to eat to help her go poop more. They also give her lots of hugs and kisses after she remembers to have an accident. That makes her feel very happy inside!
But accidents also make a big mess. So one day, Lucy says to Mommy “I don’t wanna wear undies anymore.” Mommy says “Your undies are wet and stinky most of the time now. Do you wanna try wearing diapers like a big girl?” Lucy says yes! Mommy takes her upstairs to her bedroom, takes off her undies, and dresses her up in a nice, comfy diaper just for her!
Doesn’t Lucy look much more grown-up? Lucy loves the way her diaper hugs her hips, and how it crinkles everywhere she goes.
Daddy is very proud of her too! Together, Mommy, Daddy, and Lucy throw away all her yucky baby undies. She sure doesn’t need those anymore!
The next day, they drive to the store to buy her a whole bunch of new presents! A changing table, a diaper pail, wipes, powder, oil, and of course, lots and lots of diapers!
Lucy uses her diapers all the time now, just like Mommy and Daddy. She can never tell when she has to go pee-pee or poopy anymore, but when it does, it feels very, very good! Whenever she goes pee, her diaper gets warm, soggy, and squishy. Going poopy feels even better! Whenever she goes poo-poo, her diaper fills up with warm, squishy poo-poo, and gets very, very stinky! But Lucy loves it, much better than using the potty! She especially loves sitting in it on her trike! Mommy and Daddy say it’s a good thing to enjoy the special feelings and the special smells our bodies make.
Getting changed feels very good too! Whenever Lucy decides she is ready for a clean diaper, she talks to Mommy or Daddy. They take her upstairs to her room. Lucy loves lying down on her new changing table! Mommy or Daddy undo the tapes on her diaper, and see all the mess she made! They use the wipes to make her bottom nice and clean again, then they cover it with powder and oil so she doesn’t get a diaper rash. Then, they slide the new diaper under her bottom, do the new tapes, and Lucy is nice and clean again!
Then they put the old wet or stinky diaper in a special kind of trash can called a diaper pail. Mommy and Daddy have one in their bedroom too! “When the diaper pail gets full,” Daddy says, “we take our old wet and stinky diapers out to the big trash can outside, so the garbage truck can come take them away. The garbage truck would get awfully hungry if you didn’t make lots and lots of yummy poopy diapers for him to eat!”
Lucy loves wearing diapers like a big grown-up bunny girl! Don’t you want to grow up so you can wear diapers too?