@Twilight_Shimmer  
That’s why she looks so odd to me… Other than the stare of a thousand miles she has of course.

i just noticed Twi is missing her horn

The story:
 
“Cadence can we play house now? I’m bored!” Young Twilight sparkle age 2 still struggling with using the potty like a grown filly asked her babysitter Cadence.
 
“Twilight dear it’s almost bedtime I promised your mom I would have you in bed before she got home” You don’t want me to break a promise do you?
 
“Nooo” Twilight said with a sad look on her face. Cadence couldn’t help but be sad looking at the young foal. “Oh okay we can play for a little bit. But it’s straight to bed after okay?”
 
“Okay, Thank you Cadence!” Twilight ran over to her changing table and brought back some diapers, wipes, and powder. “Okay I’ll be the mommy and you can be the baby” Twilight laid down the diaper.
 
“Hehe sorry Twilight but those are a little to small for me. Why don’t I be the mommy?” Cadence said sitting down beside Twilgiht. “Oh it’s no problem Princess has been teaching me a lot of spells watch!” Twilight sat still building up magic in her horn and with a struggling look on her face, she soon released the magic at the diaper, after the smoke cleared the small foal diaper was now 3 times as big and could easily fit the babysitter. Candence was sitting there in shock at how a young filly could even use a spell like that. “Of course Aunty Celestia has been teaching her advanced spells already.” Cadence thought to herself. “Sorry Twilight but I don’t want to put that on.” Cadence said standing up and walked to the bed to get it ready for Twilight.
 
“Aww but you promised.” Twilight wined. “Sorry Twilight, but I’m a grown filly and I can’t be seen wearing a diaper.” Cadence was now walking towards Twilight to get her ready for bed.
 
“Aw do we have a fussy baby? Maybe she needs a change.” Twilight built up her magic and picked up Cadence in her magic and floated her over to the now oversize diaper. “hey stop Twilight what are you doing? Put me down!” Cadence was now lowered on to the diaper with Twilights magic holding her down. “hey stop this now Twilight or I’ll tell your mom you were misbehaving,” Twilight didn’t seem to hear or care what Cadence said she was struggling holding Cadence with her magic. Now Twilights diaper was now growing warmer and she didn’t seem to know. Cadence was now on the diaper with Twilight wiping her down, then powdering her flank and then pulled up the diaper and fastened them around the older pony.
 
Twilight let go of her magic with a sigh of relieve. “Yah now we can play!” Twilight yelled while walking to her toy chest and pulled out a ball to play with. “Now let play catch with the baby”. Cadence was just sitting there in shock at what just happened. “Wow I couldn’t even use my own alicorn magic against her. Aunty was right she will probably be one of the strongest unicorns ever.” A ball landed in front of Cadence, she then looked up seeing Twilight sitting in front of her ready for the ball to come back. sigh “Alright Twilight we’ll play for a couple of minutes okay and then its bed time. Your mom will be home soon okay?”
 
“Okay said Twilight” for the next few minutes Cadence and Twilight were tossing the ball back and forth, and to Cadences surprise she was having fun wearing the bulky diaper beneath her. It made sitting down on the cold floor more better, and she was enjoying seeing the girl so happy. Cadence saw that Twilights throws were becoming less accurate and that the girl was becoming more tired and her eyes looking heavy. “Hehe okay Twilight it’s bedtime now.” Cadence caught the ball one more time and put it down. “Are you wet Twilgiht?”
 
“Yes Cadence I’m sorry” Twilight said looking at the floor sad. “Oh it’s okay Twilight, I probably happened when you were using that strong magic. I bet your mom will be proud of you for being able to use such strong spells. I’ll let you in on a secret I use to wet the bed till I was 10”
 
 
“Really you did, and you think she’d be proud!! I can’t wait to show her.” Suddenly Cadence and Twilight herd something outside the door. “Twilight, Cadence I’m home are you two in here…whats going on in here?”
 
“Oh Mrs. Sparkle I…I can explain” Cadence said blushing heavily. “Mommy!” Twilight screamed running towards her mom. “Guess what Mom, I used a spell to make my diapers bigger and put them on Cadence. She use to wet the bed and I thought it would be safe to put her in one before bed.”
 
“I see” Said Velvet, is this true Cadence? “Yes Mrs. Sparkle”  
“I see, well Twilight it’s past your bedtime, and I see your diaper is wet so why don’t we get you ready for bed?” Velvet picked up Twilight and walked over toward the changing table walking past Cadence she gave her a disappointing look. Cadence couldn’t help but feel bad for failing as babysitter and looking like a foal. Cadence just sat there till Velvet was being changed. “okay Twily bedtime.” Velvet walked her daughter over to her foal bed. “Aw but what about Cadence mom she’s in diapers to so is she a baby?” Cadence couldn’t help but blush at the comment. “Well I guess your right Twily just wait here for one minute.” Velvet walked over to Cadence and keeled down beside her, “ Now Cadence, I talked to your Aunt about Twilight and she warned me about the spells shes been learning. Now I’m not mad at you but I am a little disappointing that Twilight had a wet diaper on, we are trying to get her potty trained but seeing you in a diaper might make it hard for her to try, so as punishment I’m gonna leave that on you till morning and you will sleep with Twilight okay?”
 
“Okay Mrs. Sparkle, again I’m sorry” Cadence was now on the verge of crying. “Oh come here” Velvet pulled the girl into a hug and stroked her back. “it’s okay Cadence, but maybe we can use this to our advantage. Why don’t you potty train with Twilight? That means you will be wearing diapers full time but you don’t have to use them, I think it will help motivate Twilight into using the potty, so what do you think?”
 
Cadence was sitting there thinking on one hand she would be helping Twilight but on the other she’d be wearing a diaper full time. “I guess I can give it a try for a week or 2. However not in front of Shiny Armour!” Cadence was now blushing just admitting to her crushed mom that she had a crush on her son.  
“Oh not in front of Shinning huh? Why is that?” Velvet couldn’t help but laugh at the young girl about her having a crush. “hehe just teasing you Cadence, you have a deal, and I promise I’ll give you some extra bits for your trouble. Now lets get my new baby to bed.” Velvet picked up Cadence and laid her down beside Twilight, Twilight right away pulled Cadence into a hug. Velvet couldn’t help but aw at the site in front of her. She pulled the blankets over the two and started walking out the room. “Don’t worry I won’t tell Shinning about this however if you misbehave I might just let him see you in your padded butt. Hehe” Velvet closed the door behind her and turned off the lights. Within minutes Twilight was fast asleep. “I guess this won’t be so bad” Cadence said pulling the younger girl into a hug and then soon she to was asleep.
 
The end———––

@SinnerWhoKeepsTrying1978  
If you click the link, there is one.

I’d be interested in Cadence’s explanation.

Cadence looks damn good in that diaper but.. fuck, Twilight’s facial expression is.. horrifying

Wrote something kind of similar to this, except it was Shining Armor who caught Cadence diapered.

wouldn’t take much to make up an excuse. Given how young Twi Twi here is, Cadance could just say Twilight had a magic surge and this was the end result.

Looks somepony is busted