"Dear Princess, Celesita, I never thought it could happen to me..."

Princess Celestia trailed off as she read her dearest student's latest correspondence. She blinked, then skimmed the writing again to confirm just what she was reading.

"I've never seen you do that before, sister." Luna tilted her head to the side, curious. "It must be good, if Twilight Sparkle's rendered you speechless. Wha'd she do this time? Face down another dragon? Chase off a Kraken? Or maybe she took on Ursa Major this time?"

"...no." Celestia said, and re-rolled the scroll. "It's unimportant. Bureaucracy. Government work. Red tape. You wouldn't be interested."

"Red tape doesn't make you blush."

"I'm not blushing." Celestia huffed, and tilted her chin up at a regal angle.

"Not yet!" Luna's horn glowed, and suddenly the scroll tumbled out of Celestia's orbit and unrolled in front of Luna's eyes. "So, let's see what you- oh." Luna said, her eyes widening in surprise. "Oh my."

Celestia glared. "It's none of your concern."

"Which is why I'm interested, of course." Luna said, and brought her front hooves up to strengthen her hold on the salacious letter. "I must say, you certainly know how to pick them. I never would have thought this student of yours would have such an...appetite."

"Quiet, Luna."

"I mean, one, I would expect. Two? I could understand. But all five?"

"Quiet, Luna."

"At once?"

"Enough!" And with a telekinetic yank, Celestia ripped the scroll from Luna's grasp.

"Oh, don't play imperious with me, sis." Luna's tone was infuriatingly sweet. "Remember, there's got to be somepony who won't be intimidated that easily."

"I never should have let you see this letter in the first place." Celestia grumbled.

"Too late!" Luna said, surprisingly cheery for an avatar of darkness, "And by the way? I still remember the incantation of perfected memory." she said, then paused. "...I guess that's sort of the point, isn't it? So even if you feed that scroll to your pet firebird, I'm still going to remember. Every. Little. Detail."

Celestia sputtered, and then just shook her head. Her horn stopped glowing, and the letter fell to the floor. "It's my own fault." she said. "Twilight is...very eager to please."

"That's the impression I got from the letter."

Celestia glared.

Luna smiled.

"As I was saying," Celestia said, tossing her mane, "I should have known better. Twilight Sparkle does have a tendency to be...overly thorough, at times."

"I'll say. She even included diagrams."

"Yes." Celestia sighed, "Yes she did." The god-princess rubbed at her nose with one hoof, and closed her eyes. "For the record, I never told her to send a report on...that."

"So it's extra credit?" Luna bravely fought the urge to break out laughing. It was a losing battle.

"Must you be so...crass?" Celestia groaned.

"If I can't laugh at you, dear sister, who can?"

"But you're not laughing at me." Celestia said, glaring at her sister. "You're laughing at Twilight Sparkle."

"No, I'm laughing at you. I haven't seen you this flustered in...a long time, really. It's refreshing." Luna shook some of her silky hair out of her eyes. "As for your student? I'm proud of her. Who would've thought that such a buttoned-up academic had it in her?" Luna gave a quiet little giggle, and flicked her snowy hair back behind her ear. "Then again, I've heard it's the quiet ones you have to watch out for." And no sooner had she said the words, an epiphany struck the nocturnal pony. "...which reminds me of a story I once heard about a certain sun-pony and one of the Stellar Sisters..."

"That's quite enough of that!" Celestia huffed.

"Ooh, now you are blushing."

EARLIER

"Spike! Spike! Spike!" Pinkie Pie called the dragon's name with each bounce of her hooves. "I'm so glad I found you! You're just the pony we need to see!"

"Yeah!" Rainbow Dash swooped in from whatever altitude she'd been cruising at. "I was almost afraid we weren't going to find you in time."

"Whoa guys, what's up?" Spike said, halting in his tracks.

"Spike!" Pinkie Pie said, ducking back into her saddlebag for a moment, only to come out with a very neatly-rolled scroll. "Twilight told us to find you so you could send this letter to Princess Celestia right away!"

"Yeah!" Rainbow Dash leaned down from her hovering position, so as to poke Spike in the head. "She said it's reeeeeeeeeally important. So do that magic burp thing. Quick!"

"Okay, okay, calm down." Spike said, and took the scroll from Pinkie's lips. Pinkie and Rainbow both watched eagerly as enchanted green flame washed over the paper. No sooner had it disappeared, the two broke out into maniacal cackling. Rainbow Dash even stopped hovering, touching down to lean against Pinkie Pie for support.

"Whoa, what's so funny?"Spike said, and scratched at his head.

"Oh. Uh. No reason?" Pinkie Pie said, still sniggering.

"Yeah. Uh. We just saw a...funny thing." Dash managed, biting at her lower lip. "Behind you. But it's gone now."

"What she said!" Pinkie Pie said, and the two devolved into helpless laughter, this time sprawling upon the grassy ground.

"Whatever." Spike said, rolling his eyes. "You ponies are crazy." And with that, he turned his back on the pair and meandered off.

Rainbow Dash poked her head up and watched Spike go- as soon as he was out of earshot, she looked back down at Pinkie Pie. "Heh. How long 'til you think Twilight finds out what we did?"

"I dunno! But whenever it is, it's gonna be hi-larious!" Pinkie Pie giggled some more, and got back to her hooves.

"I don't know how we're gonna top this one, Pinkie." Rainbow dash shook her head, "But who knew you could copy Twilight's handwriting so well?"

"Psh. You should get all the credit! You were the one who borrowed her little wax seal thingie so the scroll's all official and stuff!" More uncontrolled laughter followed.

"But you were the one who made up the whole story!" Rainbow Dash wiped tears from her eyes.

"But you were the one who drew the pictures! Those really were the best part." Pinkie beamed.

"Yeah, you're probably right about that." Rainbow Dash preened a bit. "But I think we can call it a team effort anyway."

"Best prank ever?" Pinkie leaned in.

"Best. Prank. Ever."