Rainbow's Foalish Fantasy

“So let me get this straight…” Princess Celestia paced back and forth in her throne room.

Twilight was sitting near the throne, Dashie nestled safely between her forelegs. They had picked up some supplies before they had hopped on the train to Canterlot that evening, and Twilight had changed Dashie into a fresh diaper before they had left. “You wanted to let Rainbow Dash live out her fantasy of being a foal for a day and the spells backfired… correct?”

“Partly,” Twilight said, laying a hoof around Dashie’s back. Her little body was trembling, though if it was out of sheer nervousness, Twilight did not know. “I cast a series of spells on her to make things more… realistic for her. Everything went smoothly until the next morning, where I had discovered that Rainbow Dash, my marefriend…” She looked down at Dashie and gave her a reassuring smile. “Had actually turned into a foal.”

“I… see.” Celestia stopped her pacing and walked up to them, then sat down. She smiled warmly at Dashie and lowered her head till it nearly touched the ground. “How are you, little one?” she asked softly. Dashie didn’t respond. Instead, she tightened her grasp on Twilight’s leg. Celestia giggled. “There’s nothing to worry about… Dashie, right?” Twilight nodded. “Your secret is safe with me, wittle Dashie. You have nothing to fear during your stay here.”

“My old tower is still available, right?” Twilight felt Dashie scoot backwards, pushing up against her breasts. Her breath caught in her throat for just a brief moment as she gasped. They were very tender to the touch and she needed them to be drained soon.

Celestia smiled at her. “Am I correct in assuming that your breasts are a result of one of the spells? They do look quite swollen, you know. When was the last time you drained them?”

Twilight lifted a foreleg to look down between her legs. “Earlier this morning. I tried to feed Dashie some foal food, but she threw it up almost immediately after swallowing it. I had no other choice than to let Dashie feed from me, but...” She bit her lip as she watched what used to be her marefriend start to mindlessly play with her own tail. “My… milk, for lack of a better term, makes her incontinent. The spell I had cast on her earlier was designed to make that happen, and...”

“And what?”

“I think that the specific combination of spells I used somehow affected the way my milk affects Dashie. I never meant for her to regress to the point of foalhood, and even though I really want for her to change back to her normal self...”

“I’m sensing there’s something else on your mind?”

Twilight nodded. “I’m having more fun with this than I thought. Calling her my foal makes me feel… I don’t know.” She blushed and glanced to the side. “I just feel all of these butterflies in my stomach, and I really do have a lot of fun taking care of her. I feel a lot closer to her because of all of this.”

At that, Rainbow looked up and nuzzled Twilight’s leg. She loosened her grip on her and cautiously stepped out from under Twilight. Dashie stared Celestia right in the face and nodded once.

Celestia locked eyes with Dashie, then glanced at Twilight. “Hold on a moment, Twilight. Can she understand us?”

Twilight nodded. “Mhm. I kept her adult mind intact throughout the process, and somehow, she retained it through her… regression.”

Celestia chuckled. “Well, this uncomplicates things a little bit.” She walked to look out the window overlooking the city. “To answer your question, yes, your tower has been cleaned and… stocked up for your arrival. I trust you’ll find everything to your liking, and I left a sizable bag of bits for you two to have some fun as mother and daughter around the city if you so choose.”

Mother and daughter? Dashie glanced up at Twilight. “Are you weally gonna be my mama?” Dashie’s tail wagged back and forth much like a dog’s; she simply couldn’t contain her excitement. Her diaper crinkled underneath her, but she paid that no mind. Her deepest fantasy was about to come true! She loved the fact that nopony in Canterlot would ever recognize her in her current state, and she had the most wonderful pony in all of Equestria to look after her.

“Yes, Dashie.” Twilight nuzzled her foal and laid a wing across her back. “You and I are going to have so much fun.”