Don't Be Such A Baby (Patreon)

 It was a quiet evening in the Tsukino household. Usagi's parents went on  a night out, while Shingo was at a friend's house having a sleep over,  and Luna decided to take a scroll around the night town. So this just  left Usagi and ChibiUsa at home. Usagi was left in charge, but her  mother told ChibiUsa to make sure Usagi did her homework, which ticked  Usagi off, feeling untrusted. As the evening went by, ChibiUsa had left  Usagi to her own devices for an hour in her room. She had hoped that  Usagi would take some responsibility, especially when she moped about  not being trusted to do her homework, but as ChibiUsa opened the door to  Usagi's room to see her laid down on her front watching anime on TV  while eating potato chips, her hopes were dead in the water.

"Usagi!" called ChibiUsa. "You were supposed to be doing your homework!"

"I'll do it later!" responded Usagi.

"It's nine o clock already! No wonder you can be trusted to do things by yourself, you're such a baby!"

"Whatever, I'm the oldest in the house."

"Erm, no you're not. I've over three hundred years old!"

"Yeah, but technically you haven't even been born yet, so that still make me the oldest AND tallest!"

"But not the wisest."

Usagi reached for the TV and switched it off.

"Oh, I haven't got the energy to deal with you. I'm gonna take a nap, then do the homework."

"Energy?You've done nothing all day!"

Usagi go up and laid down on her bed, laying on top of her bed covers not under.

"Watch me up at ten...goodnight."

Usagi drifted into a deep sleep.

"God, how does that girl manage to fall asleep so easily like a baby? How on earth are we even related?"

Angry at Usagi, she left the room to go into her own room.

 "God, someone's got to teach that crybaby a lesson." ChibiUsa thought  to herself, when suddenly, a wicked idea formed in her head, making her  grin at just the thought. "Maybe there is something I can do. I have  just the thing!"

Usagi awoke a little later feeling more chilly for some reason.

"Huh? Did someone turn down the heating or something?"

As  she rubbed the sand dust from her eyes and her mind woke up as well,  her eyes widened at the reason why she was cold, she was naked! Well,  aside from one item of clothing, an adult diaper!

"What?!? What  the hell is this?!?" Usagi wondered. She was in her school uniform  before she took a nap, but now she more resembled a teenage baby! She  tried pulling it off, but it remained stuck to her!

"Ah good, your clothes now match your brain and behavior!" laughed ChibiUsa, swirling from the chair by Usagi's dresser.

"Why, why did you do this?"

 "I'm tired of you acting like such a baby Usagi, so I've taken all your  clothes and hidden them, while dressing you into something more  appropriate!"

"Well, give me back my clothes then!"

"Only if you do as I say, and do your homework! I've locked the door with a magical lock, so you're not leaving until you do!"

"I'm bigger then you, I can easily make you undo the door!"

 "Perhaps, but then you'll never find your clothes and then what? Have  your parents return to see you naked or in a diaper? Not to mention I  took photos of you in the diaper while you were asleep. I'm sure  Rei-chan and the others would find them most amusing!"

"No, please! This is embarrassing!"

"Well then, get on my lap!"

"What?"

"Baby disobeyed moma, so baby has to be punished!"

Usagi  did as instructed. She figured that ChibiUsa was only playing a  childish game, so decided to play along, for now. Revenge would have to  come later, better to do as she said then be humiliated. ChibiUsa  proceeded to spank Usagi on the bottom, smacking her five times. Usagi  felt no pain as ChibiUsa was physically too weak to spank her hard,  however she did feel tingly in her body for some reason, the feeling  going through her whole body.

"You going to do your homework now?" asked ChibiUsa

"Nope!" smiled Usagi, not taking the situation seriously. "Baby wanna watch anime!"

"Fair enough."

She  spanked Usagi another five times. The strange sensation rushed through  Usagi's body again, but the spankings were feeling harder too. Not  massive pain, but slightly harder every time.

"How about now?"

"Awww, okay dokay!" joked Usagi.

Usagi  got up from ChibiUsa's lap and sat at her desk, opening the textbook in  front of her. She realized something was not right when she looked into  the book.

"Erm ChibiUsa, this is an old textbook. I haven't studied any of this stuff since I was twelfth!"   

"So you're refusing to study?"

"Well, I wanted to do my REAL homework, not learn what I already know..."

"Okay then, back on the lap!"

ChibiUsa  grabbed Usagi by the arm and pulled her onto her lap with surprising  strength. More spanking followed, this time around fifteen, and they  were really beginning to hurt this time, the tingling getting stronger  too.

"Oww, Oww, this is beginning to really hurt!"

"You gonna do your homework now?"

"Yes, oww, please stop! I'm feeling really strange ChibiUsa!"

"Okay then, off you come."

Usagi  jumped off ChibiUsa's lap. Walking back to the chair, something else  seemed off. Did the room suddenly get bigger? Why was the chair on her  desk bigger then her now?

"What's going on?" Usagi asked as she  turned around. To her horror, a huge ChibiUsa stood in front of her. Now  outgrown her, she was a teenager about her age wearing the dress she  once wore when she was the Wicked Lady.

"Woah! How the heck did you get so big?"

"Why don't you look at yourself in the mirror?"

Usagi  looked at her mirror, and looking back at her was a girl around  ChibiUsa old height and age, with hair like Usagi's, only shorter,  wearing the same diaper she was wearing!

"AAAAARRRRRGGGGHHHH!" Screamed Usagi. "What's happened to me?"

"It's an effect of the diaper." smiled ChibiUsa.

"The diaper?"

 "Yes, its a magic diaper. You see, every time the wearer gets spanked,  that person regresses by roughly six months per spanking, while the  spanker gains those months and progresses as such!"

"Well then change me back!"

"Nah see, you act so much like a baby a lot, maybe it's time you became one again as punishment."

"No! I don't wanna be a baby!"

Usagi tried to make a break for the door, but ChibiUsa grabbed her by the arm again, and placed her back on her lap.

"Baby's misbehaving again!"

Once  again, ChibiUsa began spanking Usagi. Her hand now bigger then Usagi's  behind, it stung Usagi to the point where she was crying just like a  baby.

"OWW, PLEASE STOP! ME DON WANNA BE...WAIT, I DON TALK  LIKE...". Usagi's words became more toddler like, her body now shrinking  to the age of three! ChibiUsa meanwhile looked in her early twenties.

"There we go! Now your body matches your behavior!"

ChibiUsa  placed the three year old Usagi on the floor, who sat down sucking her  thumb like a baby habit with tears flowing down her face. ChibiUsa  meanwhile turned on the TV.

"Ah here we go, a showv ery suited for your age!"

"I don wanna wach Barney da Dinosar!!!"

Usagi  moaned and her cries were sounding more like those of a baby now. Her  teenage years were robbed from her, this felt like a really bad dream.

"Well then, baby want her bottle?"

ChibiUsa held up a baby bottle of milk, but Usagi continued crying.

"ME WANT NO BOTTLE! WAAAAAAAHHHH!"

ChibiUsa sighed at her response.

"Well, guess there's no choice."

The pink haired child turned adult picked up her baby mother and put her on her lap once more.

"I wasn't going to regress you further then this Usagi, but if you can't stop acting like a baby..."

"NO NO NO, ME BEEE GOOD! PWEEEZE DON DO IT!"

 "There won't be many spanking left, so it'll now be one month per  spanking. You know at this rate, I'll be known as Usagi, and you'll have  to be ChibiUsa, huh."

ChibiUsa went easier this time, with each  spanking becoming me like a tap on the behind as going full force would  really hurt Usagi in this state. While not feeling pain from the gentle  taps, Usagi still cried and moaned as she knew she was getting younger.

"WAAAAAAAH, NO PWEEEEEASE! I DON WANNA BE A...GOO GOO! AAGO GOO GOOOO! AGOO AGOO!!!"

Usagi  could no longer talk now. Her body now too young for words, and hair  now shorter then ever, no longer having the ridiculously long pigtails,  just the short hair on her head. The pink haired adult finally stopped.  All that remained of Usagi on her lap was a crying one year old baby,  while now ChibiUsa was now in her mid twenties.

"There we go!" smiled ChibiUsa. "This is the youngest you can be by the diaper."

She held up Usagi in front of her.

 "Wanna know how to change back? You've gotta relive your childhood all  over again! That's the only way you'll learn Usagi, and every time you  step out of line, I'll spank you until you're one years old once again!

The tears did not stop from Usagi's eyes, her life robbed in front of her eyes and now made to be a baby again.

 "Don't worry crybaby, I'll use P-Luna on everyone so they think you've  always been a baby and I'll take your role as Usagi and Sailor Moon!  Just think, next time you seen your friends as a teenager, they'll be in  their forties by then, or possibly older!"

The crying increased in sound.

"Awww, bet I know what you need."

The  pink haired adult slipped off her dress and lifted up her top,  revealing a large breast, and placing Usagi's head close to it, who  tried to push it away from her.

"You STILL misbehaving Usagi?"

"Goo goo goo!" Usagi said scared.

 "I'm not giving you the bottle, you had your chance! You know, I could  just use P-Luna on you and make you a good baby that accepts feeding! Of  course, I could WAY worse things as well to humiliate you further, your  choice."

And so, with a sad look on her face, Usagi accepted the breast and sucked on the milking nipple like a good girl.

"Good baby! That wasn't so hard was it? Your moma and daddy will be home soon!"

Usagi  didnt respond, just kept on accepting milk from her. ChibiUsa knew she  was creating a time paradox doing this to Usagi, but she had ways of  preventing the flow of time collapsing with her magic. Besides, her  being in this time zone was a paradox of its own, and she would insure  certain events would still happen, one way or another, when she crossed  that bridge someday.

For now, she would be a older sister and part mommy, ensuring Usagi would not become some a klutz THIS time!

The End.