Spike sighed wearily as he trudged out of the kitchen, carrying a platter of nachos.

The Great And Ridiculous Trixie had, to his and Twilight's dismay, taken it upon herself to decide she was moving into the library indefinitely...

"You want to WHAT?!" Twilight yelled.

"You heard me...'Princess'," Trixie said. "Trixie WILL learn the secret of what makes Twilight Sparkle THINK she is so much greater and more magical than Trixie—"

"Uhh, hello?" Twilight said, waving a wing at Trixie. "Evolved into an alicorn here? Kinda proof-of-concept?"

"And until Trixie has fully studied you and your magic," Trixie proclaimed, "Trixie will remain here, in your home, observing you day and night! Once Trixie has uncovered your secrets, Trixie will apply them to her own magic...and then Trixie will stand at the top of all unicorns in Equestria!"

"And I'll still be an alicorn, so...have fun with that," Twilight said.

Despite Twilight's initial complaints, she had allowed Trixie to stay at the library and study her. It didn't take Spike long to understand why:

For the first time since becoming an alicorn princess, Twilight had found somepony she wanted to lord it over. As unfailingly humble as Twilight was most of the time, she wasn't without a competitive streak, and Trixie...well, she pretty much brought out the worst in everypony.

So while Twilight had gone to incredible lengths to ask everypony in Ponyville to treat her the same as always, in the privacy of the library...

An earsplitting shriek nearly made Spike drop the nachos. "AAAH! BATS! GET THEM AWAY!"

A single purple fruit bat flapped around in the center of the library. Trixie was cowering on the floor, covering her face with her hooves.

Twilight rolled her eyes. "It's just one little fruit bat. It won't hurt you."

"WHERE DID IT EVEN COME FROM?!"

"Oh, I teleported it here from Sweet Apple Acres," Twilight said offhoofedly. "I just needed a live specimen to show you this neat spell." The bat suddenly halted in midair, wrapped in Twilight's magenta aura. "Hold still little guy...wouldn't want to miss and hit Trixie by mistake!"

Trixie looked up as Twilight's horn glowed brighter. A beam of magic shot out, striking the bat...which promptly transformed into a ripe, juicy orange with bat wings. The magic aura faded from around it, and the bat-orange dropped out of the sky, its new citrusy body too heavy for its wings to support. Twilight zapped it with her horn again, and it disappeared.

"But...that's...!" Trixie gasped.

Twilight smirked. "Impossible?"

"No. Disturbing," Trixie sniffed.

The library door opened, and Rainbow Dash poked her head in. "Twilight! Are you busy?"

"Not terribly, why?"

"The Ponyville Post Office has a major mail catastrophe! The sorting room's all derped up and the regular clerk just snapped and mailed himself to Las Pegasus! Think you can lend a hoof? Maybe use those super awesome organizational skills of yours to fix this mess?"

Twilight teleported to the door. "As a Princess of Equestria, it is my sacred duty to ensure that all citizens receive their mail on time and with no delivery errors!" she said proudly.

"Uhh...okay?" Rainbow said, blinking. "We'd better hurry."

Twilight smirked at Trixie. "I guess teaching you that spell will have to wait until later," she said before launching herself into the air after Rainbow Dash.

"The Great and Powerful Trixie does not NEED to be TAUGHT spells like some FOAL!" Trixie shrieked at the open door. "Trixie is perfectly capable of learning spells on her own! And Trixie does not want to learn THAT spell anyway."

Spike placed the nachos on the table. "So pick a different spell to learn while Twilight's out."

"Trixie shall do s—oh, these are excellent nachos."

For the next hour, Trixie engrossed herself in one of Twilight's advanced spellbooks while scarfing two whole platters of nachos. Spike talked her into trying out the mustache spell; she managed to cast it successfully, but could only produce a tiny toothbrush mustache. She tried to turn a rock into a top hat, but only succeeded in producing a ragged, patched newsie cap.

Spike, now wearing said newsie cap and toothbrush mustache, drummed his claws on the table. "I don't understand it," he said. "Those spells are so easy! Twilight mastered them ages ago. Heck, she had the mustache spell down cold the first time you showed up."

Trixie ground her teeth. "You have made it QUITE plain to Trixie that you are Sparkle's biggest fan," she said. "Now, if you would kindly pull your scaly snout OUT of her royal hiney..."

"Hey!" Spike snapped. "I do NOT have my nose up Twilight's butt!" He sighed. "If I have my nose up anypony's butt, it's Rarity..."

"That silly clothes horse with the ridiculous mane?" Trixie scoffed. "Whatever do you see in her?"

"She's gorgeous, generous, kind, classy...she can locate gems with her magic..."

"Spare Trixie the glowing essay," Trixie said, rolling her eyes. She turned another page in the book, and her eyes lit up. "Oh? This spell certainly looks worthy of being cast by Trixie..."

"What spell is that?" Spike asked, leaning in for a look. His eyes widened. "The Body Double spell? Uhh...I don't think that's a good idea," he said.

"Oh? And whyever not?"

"It's just...Twilight's never cast that spell. She says it doesn't really have a practical application."

Trixie raised an eyebrow at Spike. "Right. Because giving out random mustaches is so useful." She pointed with a hoof. "Stand over there. Trixie will amaze and astound you by creating a flawless body double!"

"Yeah, okay, this could be good for a laugh," Spike said, padding over to the indicated spot.

Trixie's horn began to glow. A few sparks fizzed and popped at the top. She narrowed her eyes and furrowed her brow. A faint sizzling sound filled the library.

A bright flash engulfed Spike...

...and suddenly, Trixie, the library, and everything in it were enormous.

Spike looked up at the mountain-sized mare. "Uhhh...what just happened?"

Trixie blinked at Spike, who was now slightly smaller than a mouse. "Oh dear," she said. "It appears Trixie abra'd when she should have cadabra'd."

"WHAT DID YOU DO TO ME?!" Spike roared...except at his current size, it was more like a loud squeak.

Trixie rubbed the back of her head with a hoof. "Ah...heheh...it would appear that THE GREAT AND POWERFUL TRRRRRRIXIE!! has discovered a shrinking spell."

Spike facepalmed. "Great. Just great. Hurry up and undo this, would you?"

"Of...of course! Just...give me a moment to find a book with a counterspell..."

"I can't find a counterspell!" Trixie wailed.

Spike watched her run around the library in a panic. Piles of books littered the table and floor. She had spent over an hour searching for a counterspell that would restore him to normal size. He sighed. "It's okay, Trixie," he said. "Twilight'll be home soon, and she can fix this."

"NO!" Trixie declared, stamping a hoof. "Trixie refuses to bow to Twilight Sparkle and beg her to undo Trixie's mistake! Trixie will FIX this problem HERSELF!" She paused, then added, "Besides...if Twilight sees this, she will probably throw Trixie out on her Great and Powerful Rear."

Spike snickered. "Powerful rear...heh...after all those nachos, maybe."

"Quiet, you!" Trixie snarled.

The door began to open. Trixie's eyes widened.

"I'm back!" Twilight called lightly. "Ponyville's mail crisis is not only solved, but everypony got their mail almost an hour early!"

Trixie's jaw hung open as the door slowly opened. She pranced lightly in place on her hooves, looking from the door to the shrunken Spike.

Then, quick as a flash, she darted from the bookshelves to where Spike stood...

...and sat on him.

"HEY!" a muffled squeak erupted from under her butt.

Trixie cleared her throat. "Ahem. Welcome home, Sparkle," she said primly.

"Hi Trixie. Anything interesting happen while I was gone?"

"Oh, nothing much. Trixie read many spellbooks..."

Twilight looked around at the mess. "Yes. Yes you did."

Trixie laughed half-heartedly and began levitating strewn books into neat piles.

"Oh, don't bother. I'll get Spike to reshelve those later," Twilight said. "Where IS Spike?"

"Spike? Why...I believe he said...he was going to visit Rarity?" Trixie hedged.

Twilight nodded. "Alright." She stretched and popped a wing. "I could use a snack. Do you want anything?"

"N-no...Trixie is fine."

As Twilight trotted into the kitchen, Spike struggled to push out from underneath Trixie. "What the HAY?" he asked indignantly.

"It was all Trixie could think of!" Trixie squeaked. "Sparkle MUST NOT see you like this!"

"Eh, she'd understand," Spike said. "Magical accidents happen to her all the ti—"

"I've got potato chips!" Twilight announced, walking back into the library with a large bowl of potato chips and a bottle of cola. Trixie quickly squashed Spike underneath her butt again and squirmed in place to make sure he was hidden. "So, Trixie, I was thinking," Twilight said as she poured herself some cola and grabbed a few chips with her magic, "I can write out a daily horn training planner for you. You know, to help hone your ability while you learn new spells."

"A-huh," Trixie grunted, grimacing as she shifted slightly.

A roll of parchment spread out in front of Twilight as she brought out ink and a quill. "It shouldn't take more than thirty or forty minutes to write out a schedule..."

Spike couldn't see anything. Trixie's ample plot was efficiently blocking all light and muffling most sound. On the plus side, her coat was quite soft. It was, however, starting to get hard to breathe.

"Yeah, I don't care about Trixie's ego," Spike muttered. Probing around until he found what felt like the most tender area, he opened wide and clamped down with his sharp fangs.

"YIIIIIIIIIII!" Trixie squealed, eyes bugging out.

Twilight blinked. "Something wrong, Trixie?"

"Ah...! N-no, no problem here!" Trixie said hastily. Face red, she stammered, "T-trixie has...an itch...in a verYYYYYYYYYYY! ...sensitive place."

Twilight tilted her head. "I have a cream that might help with that. Want me to go get it?"

"N-no, that's fine. I'll manage." Trixie cleared her throat, attempting to still her squirming and calm herself. "Ahem. Continue?"

Twilight frowned. "Yeah, I'll go get that cream. Be right back."

As soon as Twilight teleported away, Trixie leapt up and whirled around, scowling down at the shrunken Spike. "WHY did you do that, you wretched wyrm?!"

"You SAT on me," Spike said, arms crossed. "You shouldn't sit on dragons unless you want your big blue butt bit."

"That was not Trixie's BUTT you bit, you brute!" Trixie hissed. "You bit Trixie on the teat!"

Spike shrugged. "Butt, teat, whatever. It got you offa me, mission accomplished."

"Now listen carefully, you," Trixie seethed. "You WILL remain hidden and out of sight until Trixie has time to find a counterspell. Trixie REFUSES to allow Twilight Sparkle to know—"

"To know what?" Twilight's voice called from the stairs.

Trixie yelped and dove on top of Spike, laying flat on the floor. "To know...that...Trixie is experiencing the onset of estrus!" Trixie said as Twilight glided downstairs.

Twilight folded her wings at her sides and laughed. "Why didn't you say so? That's nothing to be ashamed of! Actually, I just got some delicious herbal tea from Zecora. It's supposed to be VERY good for suppressing estrus symptoms."

"Zecora? The zebra whose doorstop derailed my dastardly dominion of Ponyville?"

"The very same," Twilight said, trotting to the kitchen. "It'll take a few minutes to make the tea."

"Take your time!" Trixie said lightly. As soon as Twilight was gone, she stood up and floated Spike out from beneath her. "Listen carefully, you little—"

"By the way, do you take your tea with honey or milk?"

Trixie quickly stuffed Spike in her mouth, turned to face Twilight, and nodded rapidly.

"Which one?"

Trixie shrugged.

"Both?"

Trixie nodded.

"Okay. Back in a few!"

As Twilight returned to the kitchen, Trixie spat Spike out. Spike glowered up at her, covered in saliva. "You need a breath mint," he informed her.

"You're one to talk," Trixie said. "You taste like an old handbag."

"This is ridiculous!" Spike cried, throwing his claws up in the air. "Just tell Twilight what happened!"

"Never!" Trixie declared.

"So what, you're just going to sit on me every time Twilight walks in? Shove me in your mouth? It'd be pretty hard to drink tea with a mouthful of dragon, and you can't just plant your plot and not move."

Trixie frowned. "You have a point. Hiding you by sitting on you or shoving you in my mouth isn't going to work." She rubbed her chin. "Trixie is going to have to take more extreme measures." She grimaced. "Trixie has an idea. She doesn't like it, but...Trixie must do what she must."

"What're you talking about?" Spike asked.

Trixie smirked. "Prepare to go where no dragon has gone before!" With that, she enveloped Spike in her magic, levitating him toward her flank.

"Hey, what're you—"

Trixie lifted her tail; Spike's eyes widened as he floated ever closer to the one part of Trixie's body he had the least interest in being anywhere near.

"Okay Trixie, you win," he said shakily. "I get it. You don't need to GAH!"

Just as Twilight called out "Tea's ready!" from the kitchen, Trixie stuffed Spike up her twat.

Twilight walked out with the tea tray held in her magic. She observed Trixie, who was red-faced and shifting her flank awkwardly. "Goodness, you weren't kidding!" she said. She conjured a velvet pillow and placed it in reach of Trixie's posterior. "Here, sit on that. It'll be more comfortable than the wooden floor."

"Thank you," Trixie said, plopping her plot on the pillow as Twilight poured and served tea, adding milk and honey to Trixie's, and lemon and a sugarcube to her own.

"So, what've you been working on while I was out saving the post office from certain doom?" Twilight asked casually. She levitated over an open book that lay on the table, read it, and giggled. "The body double spell? It's a good thing you didn't try casting that." She paused. "You didn't, did you?"

"Err...no?" Trixie hazarded.

"Good," Twilight said. "There's a page missing from this book that contains the second half of the spell." She pointed to the page numbers; Trixie hadn't noticed before that they skipped. "It's just as well," Twilight said with a shrug. "The body double spell isn't as useful as it sounds. It just makes a static copy of you that disappears after a few minutes. You'd get more use out of a cardboard cutout." She giggled.

Trixie forced a laugh and took a sip of her tea. "This is very good tea," she said. "Where did your friend get it?"

"Oh, she blends it herself," Twilight said. "She lives in the Everfree Forest. It's apparently full of exotic herbs and teas that don't grow anywhere in Equestria."

"Isn't that a bit...dangerous?" Trixie asked, blinking. "Living in that dreadful place, braving its dangers for...tea?"

"Oh, the Everfree Forest isn't that bad," Twilight said. "I mean, yes, it can be a little wild and dangerous, but my friends and I have been in there lots of times. We've even been fixing up the old castle there...you know, the Ancient Castle of the Royal Pony Sisters? It's kind of our clubhouse." She grinned. "In fact, I've got a couple of books I borrowed from Celestia's ancient library upstairs. I'm returning them to the castle after I finish reading them, but...I'll go get them." Twilight stood up. Her horn started to glow...then stopped. "You know, I think I'll actually walk upstairs. I don't want Rarity giving me that disapproving smirk next time I have to get fitted for a dress." She trotted over to the stairs.

Once she was gone, Trixie heard a faint sound from her nethers. Casting a quick amplify-hearing spell, she stood up and looked at her rear. "What was that?"

"I'm being smothered in here! Smothered AND drowned!" Spike complained.

"Oh, pipe down. Think of it as 'training' if you ever get anywhere with that snobbish ponyfriend of yours."

"Seriously?"

"You have the honor of being inside the Great and Powerful Trixie! You are the first male who can claim that honor..." Trixie trailed off and her ears flattened against her head. "Trixie is very depressed now."

"Hey, what's this bit?" Spike asked. Trixie felt a sudden sharp jolt of...sensation as Spike's claws raked across her clit.

"You will UNHAND the Great and Powerful... BIT right NOW!" Trixie shrieked.

"Is everything okay down there?" Twilight asked as she descended the steps.

Trixie quickly sat down again, face and ears burning red through her coat. "Fine! Everything's just fine!" Trixie squeaked.

Twilight raised an eyebrow. "I guess I should've made that tea stronger."

"The Great and PowerfUUUUUL Trixie just needs a coooOOOOOOOLD!! ...shower."

"Hmm. Or...a spell for quieting estrus!" Twilight said brightly. "I do happen to have a spell for that...I've never needed it myself, but I've always wanted to study its effects on a particularly problematic cycle." She frowned. "Fluttershy won't let me cast it on her." She walked over to a shelf and began browsing. "Now, which book was that in...oh, if only Spike were here, he'd know..."

"I'm...going to the bathroom," Trixie said, rising from her cushion. "I need to—"

"I! CAN'T! BREATHE!" Spike gasped out from her hind end, poking his head out of her vulva.

Twilight's head snapped around, her ears twitching. "Did you just hear something?" she asked.

Trixie blinked. "Uh...queef?" she ventured with a sheepish grin.

Twilight crossed her eyes and scowled. "Gross!" she said, before turning her attention back to the shelves.

"I'll be back in a minute," Trixie said breathlessly, charging up the stairs. Each step jostled her passenger, eliciting a fresh gasp. Once she was safely enclosed in the bathroom, she leaned against the tub and let out a sigh. Her horn lit up, and she extracted Spike. She turned to face him. "Are you TRYING to get Trixie in trouble?"

"No, I'm trying to not die from the stench," Spike said. "You should probably see a gynecologist. I'm pretty sure it's not supposed to smell like that back there."

"I'll have you know Trixie's tunnel is fresh and delightful!" Trixie said with a dainty sniff.

"Right," Spike said, rolling his eyes. "Anyway, I'll just stay upstairs while you keep Twilight busy—"

The bathroom door flew open. "I found the spell!"

Trixie wheeled around, rapidly shoving Spike back into her pleasure pocket, and met Twilight with a feverishly bright smile. "That's good," Trixie said.

Twilight tilted her head. "Weren't you going to take a cold shower?"

Trixie nodded her head rapidly. "Yes! I was! But now I'm not."

"Oh...kay," Twilight said. "Anyway, come back downstairs. I'll cast that spell on you, and then—"

"Actually, Trixie has a better idea," Trixie said. "Trixie has a sudden craving for cheesecake."

"Oooh, that DOES sound good," Twilight said. "I'll be back in a minute!" She teleported away.

Trixie sighed. "Whew. That buys Trixie some time to find a counterspell." She trotted back downstairs. "Now, which book might—"

"Ahem. Forgetting something?" Spike asked.

"Oh, yes. Of course," Trixie said. "Umm...you can...let yourself out, I trust?"

"I've been TRYING to get out of your skunky twat for the last two minutes," Spike said. "I think I'm stuck..."

"Oh, nonsense," Trixie scoffed. Her horn lit up, and she began to extract Spike once again...

A frown crossed her face. She tugged harder.

She let out a whimper.

"Ahem. Spike?" She gave a nervous false laugh. "Trixie believes...you might be...stuck."

"Ya think?"

"Ahem. Yes. Perhaps..."

"Uh-oh," Spike said.

"Uh-oh? What do you mean uh-oh?"

"Trixie? I think...Princess Celestia is sending a letter..."

"I'm back with the cheesecake!" Twilight sang brightly as she reappeared, a box balanced on her back.

Trixie stared. "Already? But—"

Suddenly, Trixie felt like her clitoris was on fire.

Mostly because her clitoris was, in fact, on fire. She screamed and jumped into the air, eyes nearly popping out of her skull. She seized the cheesecake from Twilight's back, levitated it out of the box, set it on the floor, and sat in it, grinding her pussy into it and splattering strawberries all over the library.

Twilight's eyes narrowed. "Alright, Trixie. What's going on here?"

"Going on?" Trixie asked, laughing sheepishly. "Why would anything be going on?"

"Estrus is one thing, but this..." She frowned. "If I didn't know better..." Twilight's horn began to glow.

"Wait, what are you doIIIIING!" Trixie cried. Her rear end shot into the air of its own volition. With a wet, slick pop, Spike flew out of her pussy and bounced across the floor, trailing Trixie's fluids.

"Well, there's the problem," Twilight announced flatly. "You have a baby dragon stuck in your vagina."

Trixie rounded on Spike and glared down at him. "How DARE YOU take advantage of an innocent virgin mare! If you had balls, Trixie would kick you in them!"

"Oh, I've got balls. Seriously, I've got like, seven of 'em. But I'm not telling you where they are."

"...you have seven balls? Seriously?!"

"Uh-huh. All dragons do."

Twilight cleared her throat loudly. "Ahem! WHAT is going on here?!"

"Trixie has been VIOLATED by your pet lizard!"

Spike crossed his arms. "Yeah, right. Twi? A little help here? The Great and Powerful Weirdo here shrunk me and hid me up her hoo-ha." He paused. "Oh, and I lost a letter from Princess Celestia up there too."

Twilight stared at the two of them for a long moment...then snickered. "I should be really mad right now, but..." She doubled over, giggling uncontrollably. "This is just too f-funny!"

"Yeah yeah, hilarious," Spike said, rolling his eyes. "I'm traumatized for life and you're laughing it up."

"HEY!" Trixie cried indignantly. "YOU'RE traumatized? It's MY body you—"

"Why didn't you just hide him in the book return box?" Twilight asked, still giggling. "I mean it's right over there."

Trixie slumped. "Trixie...never thought of that."

"Poor Spike," Twilight said. "I know you wanted your first time with a mare to be special...and to be with Rarity..."

"Yeah I think I'm good on pony poon for...oh, EVER," Spike said, wiping gunk from his scales. "Can you change me back now? Please?"

"Sure, Spike," Twilight said. Her horn lit up, and Spike reverted to his normal size.

"I'm gonna go take a shower. And then a bath. And then a bubble bath," Spike announced, storming upstairs.

As he departed, Twilight asked, "So how DID you shrink Spike? I mean...I don't even know any shrinking spells, unless you count the spell that turns ponies into Breezies..."

Trixie looked away bashfully. "That, uh...body double spell? The one with the missing page? Trixie may have...miscast it."

Twilight blinked. She popped over to the book, read the first half of the body double spell, then the half-spell on the page opposite it. Her eyes widened. She aimed her horn at a chair, which immediately shrank. "Interesting. I'll need to study this. You may have actually accidentally created a new spell, Trixie!"

"Really?" Trixie asked with interest. "Does this mean Trixie can become an alicorn?"

"No." Twilight smirked. "But you CAN clean up that mess. And then go to Sugar Cube Corner and buy us another cheesecake."

Trixie sighed. "Oh, very well."

"And then you can write a letter to Princess Celestia..."

"Trixie thinks not, Sparkle."