A/N: All credit for the plot goes to BigBadFluttershy. All credit for the insanity... Still goes to BigBadFluttershy. But this high writing goes to me. We all good? OK, moving on. I apologize in advance for any disturbing mental images or a lack of quality.
"Look, Derpy, I know you never agreed to do this..." Twilight started as she slowly circled around the pony in question.
"These ropes are too tight!" Derpy complained, struggling like a fish (I think that's a good comparison). "And how did you find me anyways?! I think I was on my mail route."
"I have my resources!" Twilight answered quickly. Her eyes darted left and right rapidly, which always happened when she got nervous. "I-I-I didn't shove a tracking device up your ass!"
Drop a pin. You hear that? It's what was running through Derpy's mind at that specific moment.
"Err... Moving on, I want you to help me with a spell. FrIeNd," Twilight told Derpy, hoping to change the subject.
"With what? I'm a pegasus, I think," Derpy muttered.
"You are a pegasus," Twilight confirmed. "And that's exactly the kind of pony I want to experiment on."
Blink. Derp blink. "What do you want to do?"
"OK, remember that time I gave Rarity wings?" Twilight asked. "Don't think too hard about it. I knows what happens to you, FrIenD. Anyways, I pulled a spell out of nowhere the other day where I can give any random bucking pony a horn! I could have tried it on Applejack, but she's been kind of annoying lately, not that I would ever say that to her face, and Pinkie would destroy the whole damn world."
"...And what makes me a better candidate?" Derpy asked the first legit question all weekend.
The purple mare opened her mouth to answer, but the only thing that came to mind was crystal pony porn. "I... Don't know why..." she replied in a half murmur. "But, anyways, I'm going to give you a horn for three days, FrIeNd."
"But I don't wanna horn!" Derpy exclaimed. "It's gonna interfere with my mail route!"
"Wow, I thought you were retarded before," Twilight commented. She quickly said mere fractions of a second later, "NOT THAT I MEAN TO OFFEND YOU OR ANYTHING, FrIeNd!"
"Oh, you can't upset me, Twilight!" Derpy smiled. "But I just don't feel too safe doing this."
"C'MON! This'll be the scienmatific discovery of the bucking year!" Twilight whined. "Do you want to get in the way of FrIeNdShIp?!"
"No, but my mail route! My mail route! My MAIL ro-"
"I'll give you a muffin!" Twilight told Derpy sweetly.
Derpy's "bonds" broke and she stood up on all fours, looking as brave as she could with her eyes looking north and south respectively. "Go ahead, make my day!" she cried.
Only a little surprised by Derpy's sudden courage (as in none), Twilight started charging the spell. There was a while wait before something else happened and that was Twilight sweating.
"This is not gonna backfire!" Twilight reassured herself. "There is no way in hell this can backfire!... Hey, what's that fly doing th-"
Said fly landed on Twilight's nose, causing her to sneeze as much as she sweating. Sadly, she also let go of the spell at the exact same time and started shooting every which way but the Royal Canterlot gardens, mainly hitting somewhere that wasn't Derpy's forehead. She stopped a few minutes later and killed the fly.
"Damn flies, always getting in my bucking way!" Twilight shouted. "Not that ever had before, BUT THEY'RE CONSPIRING AGAIN..." she looked at Derpy and noticed something was off. "...st me..."
"What? What is it?" Derpy asked, acting like Twilight was a dog.
"I... I just don't know what went wrong!" Twilight said to herself.
"That's my line!"
"Forget that!" Twilight snapped. "Just... Don't be mad at me and look between your legs..."
Derpy nodded vigorously and looked between her legs. She looked back up and asked, "Which one? I got two pairs and I-"
"THE SECOND!"
"OK!" Derpy nodded again and looked between her second pair of legs. And what did she see? A ten-inch dick. Yeah. This is the point where you put on the "Tomfoolery" music. Anyways, she (Derpy) looked back up, horrified. "I... I... I..."
"I'M SORRY, I'M SORRY, I'M SORRY!" Twilight said. She was crying like an idiot, praying to the high bucking heavens Derpy wouldn't be mad at her. "I DIDN'T MEAN TO! IT WAS THE FLY'S FAULT!"
"I... I... I..." Derpy stammered, her mind trying to complete a full sentence.
Twilight was trying really hard at this point to calm herself down, whispering to herself about nopony ever finding out. Remember, she had gone completely insane and she would be locked away in normal circumstances, but Celestia had WAAAAAAAAAAAAAAAAAAAAAAAAAY too much confidence in her.
"I... I..." Derpy continued. "I... I... I... I can buck mares, right?!"
"I'm so sor- what?" Twilight asked, confused. "You want to know if you can buck... Mares?"
"Yeah! Can I buck mares?!" Derpy repeated herself, getting excited.
"I suppose so!" Twilight answered, knowing exactly where this was going.
Derpy gasped, smiling the biggest smile she had on all week. "THANKS TWILIGHT, I GOTTA GO!" she shouted happily, running off.
Twilight blinked and MAGICKED over a copy of Shut The Blinds. "I need something stupid to forget this..."
"Stop insulting the blind!" Rainbow Dash cried.
"You don't even know what I'm reading!" Twilight retorted. "Now get out of my house!... FrIeNd!"
Meanwhile, at the Hooves's residence, Screwball was in Derpy's bathroom taking a bath with Dinky.
"...And, as you can see, this is King Sombra is the most useless villain ever conceived " Screwball finished with a smile.
"You needed to take a bath in order to tell me that?" Dinky enquired. "And she isn't my mother, she just looks after me..."
"I've always wanted to explain this kind of stuff in oatmeal flavoured bath water!" Screwball answered. Immediately she said that, she took a drink of the water. "Taste too much like you. Screwloose, ya need to get some more oatmeal!"
Screwloose suddenly came out of the medicine cabinet and started for the door. However, right as she was about to leave, Derpy came in and crushed Screwloose with the door.
"Lookit what I got!" Derpy yelled happily, standing on her back hooves.
Screwball squinted at Derpy. "A... A tail ring?" she suggested.
"I shouldn't be looking at this," Dinky told Screwball all worried like.
"I'm guessing here!" Screwball said, doing the "I can't believe you!" motion. "Let me do it!"
Dinky nodded and moved away a couple inches.
"Um... A... An iPod?" Screwball tried again. "Happy Wheels? A new record? A Kool-aid cup? Black Snooty, Black Snooty! Adele! A wooden toast-"
"Close, but no cigar!" Derpy interuptted. "It's... A penis! I've got a penis!"
Screwball's eyes widened and she started laughing.
"What's so funny?" Derpy asked, not really offended, but somehow sounding like it.
"Screw... Screwloose!" Screwball said in between laughs. "Get... Get the... Frosting and sparkles!"
Hearing those words, the door of which Screwloose was behind exploded. The light blue pony saluted and ran off, coming back a few moments later with a bucket. She dropped it off and went to get the rest of the stuff she needed to get.
"What's so funny?" Derpy asked again.
"Now... Now..." Screwball gasped, trying to catch her breath. "Now my fanart is almost correct!"
"You draw?" Derpy was shocked and stunned.
"Well, i got Pinkie to help me in some places," Screwball admitted. "Back to the art, it's not perfect! It needs... SOMETHING! Namely frosting and sparkles!"
"That makes sense!" Derpy said, seeing why it was funny.
"I know, right?" Screwball agreed, going back to the laughter. "It all makes sense!"
Dinky was really confused by all this. So you know exactly how she feels.
"So what else was in your art?" Derpy asked.
"Your dick..." Screwball slowly rubbed her chin as she thought about it. "In Fluttershy's mouth!"
The derped pony thought about it. "I can do that!" she said happily. "I think I even know where she is at this exact moment in time!"
Screwball gave a happy squeal for no good reason as Screwloose came back with the sparkles and frosting Screwball wanted. She dumped both into the bucket and gave it to Derpy.
"Thanks!" Derpy said, taking the bucket. She looked at the bucket for a few seconds. "What am I supposed to do with it?"
"Stick it in it!" Screwball explained.
Assuming she knew what Screwball meant, Derpy stuck her cock into the bucket and pulled it out a few seconds later. It was completely covered.
"That felt weird..." Derpy commented, inspecting her newly decorated member.
"Eh, it'll feel better later," Screwball told Derpy. "Now go out! Go get Fluttershy!"
Derpy made an "Mm-hm" noise and ran out. Screwloose watched this and whined a little.
"Don't worry, girl," Screwball said to Screwloose. "Your time will come. Now go me my oatmeal!" She then turned to Dinky. "And you! Stop being so delectable!"
"I'm... Sorry?" Dinky tried, not sure what to say exactly or what even happened.
Cutting back to our derp-tagonist, the pegasus was searching PonyVille for Fluttershy. Sure, she (Derpy) knew where she (Fluttershy) was, but she... I dunno what was running through Derpy's head. Let's check, shall we?
Gotta find Fluttershy, gotta find Fluttershy, gotta find Fluttershy, Derpy thought, not giving any good insight into her character. Gotta find Fluttershy, gotta find- oh, there she is. Knew it! Totally knew it!
Speaking of Fluttershy, she was taking to Rainbow Dash near where Desmond had a barrel in the market place.
"Admit it, Fluttershy, you liked being in that fanfic!" Rainbow said with a small chuckle, poking her compardre.
"Not a whole lot, really," Fluttershy mumbled. "Can we stop talking about it?"
"Whatever ya want, Flutters," Rainbow dash said. "Admittedly, I want to forget about it as well."
"That's good. Now let's-" Fluttershy began, but stopped when Derpy came up to the two, hovering right above them.
"Hey, Rainbow Dash!" Derpy exclaimed, looking at said daredevil.
"What is it, Derpy?" Rainbow Dash groaned. "It better not be about what I think it's about!"
"It's not..." Fluttershy answered for Derpy, staring at Derpy's polla. "It's... I just... Eep..."
"What? What is it?" Rainbow Dash demanded Fluttershy. "You know I'm blind! Why doesn't anypony remember that?!"
"Derpy... Has... It's a... How'd she..." Fluttershy stammered, trying to form a sentence that said "Derpy has a penis".
"Fluttershy, whatever it is, just tell me!" Rainbow Dash said. "Just tell me!"
Fluttershy went completely silent. Shock and horror just crushed her.
"What the-" Rainbow Dash began, but Derpy slapped her across the face. "...The buck did she just hit me with?"
Derpy got a very wide grin on her face. "My dick!" she exclaimed happily.
"...YOUR WHAT?"
"My dick!" Derpy repeated herself. "Twilight gave it to me! You're surprised, right?"
"I suppose!" Rainbow shouted, now knowing Fluttershy's shock.
"And you know what I'm going to do with it?" Derpy enquired, a stupid grin crossing her face.
Rainbow frowned. "I can't imagine what!"
"Care to tell her, Fluttershy?" Derpy asked her half-friend
"Ah gah dih eh woh mouf!" Fluttershy muffled. She couldn't say a whole lot since Derpy shoved her whole length in her mouth.
"What?" Rainbow Dash was just as confused as Dinky was.
Fluttershy wanted to say, but she felt way too embarrassed standing there with a female pair of testicles shoved down her throat. So she ran off without trying anything, Derpy being dragged along with her since the frosting had glued her to the inside of her uvula. This somehow looked more dignified then it should have.
"I'm so confused!" Dashie cried.
AT FLUTTERSHY'S...
The yellow Hammerskin had spent the last hour and a half balling her eyes out. I mean, when Chrysalis does her, it's perfectely fine. But when DERPY does it, that's a whole 'nother level. Speaking of which, the mailmare had spent the time she was there randomly orgasming and eating muffins Fluttershy just so happened to have laying around.
"Y'know, these need a little more sugar," Derpy commented, eating another pastry. She thought for a moment before adding, "I should tell Pinkie later. I hope she's not busy. I also need to get some frosting; Screwloose used the last of it. Whadda you think?"
Fluttershy tried to say something, but her mouth was much too stuffed to make any noise outside of, "Ah dah care!"
Derpy nodded and muttered an "uh-huh", noticing that she could leave Fluttershy's mouth.
"Hey, I can get out of your mouth!" Derpy announced. "You want me to?"
"YEH! YEH!"
"Sure!" Derpy chirped, flittering out. "I'm just gonna grab a few muffins and be on my way. You mind?"
"GET OUT!"
Derpy was taken aback by Fluttershy's outburst, but not for long. She grabbed a random bag that was lying around, shoved a couple muffins into it (and a bird by accident) and left.
Fluttershy blinked and thought about how it happened. "This would've never happened if that turned out to be Chrysalis," she sighed.
TRANSITION... WHEREFORE ART THOU? OH, RIGHT HERE. NEVAMIND!
Derpy decided to fly back to Twilight's place, accidentally bumping into a lamppost, a chicken, a building, a tree, a mule, a cup, a hot dog, a Fix-It Felix, Jr. arcade cabinet, the same mule as before, Rainbow Dash and a tombstone.
Walking into Twilight's place, Derpy stopped dead in her tracks and had a stunning revelation. "I can piss standing up! YES! That's amazing!"
Unfortunately, Twilight was in the bathroom reading Twilust, so she couldn't hear Derpy's loud proclamation. So a few minutes later, Twilight came out of the bathroom (whistling "Across The Universe" as well) and took a few seconds to notice that everything was covered in urine. And Derpy was laying on the chandelier, rocking back and forth while singing "Suspicious Minds".
"What the buck did you do?!" Twilight shouted to Derpy, shaking violently.
"I peed over everything!" Derpy replied happily.
"How much urine did you have in you?! Have you not gone to bathroom in days?!" Twilight was horrified and enraged. "I mean... WHAT... WHA... I..."
Derpy shrugged. "I guess I just really had to go, I guess," she answered slowly. "There's no problem with that." She then randomly fell off the chandelier, not even bothering to use her wings to slow her fall. She landed on her back, FYI. "Ow."
Twilight sighed and telepor'd downstairs, since using stairs was a waste of her time. "I've gotta take that thing away from you, Derpy," she told Derpy with an obviously fake tone of sadness. "It's too great for you to handle."
"Aw... I've been having so much fun with it!" Derpy muttered, making a cute face. "Can I please keep it?"
"And have everypony think you're a transgendered mess?" Twilight argued. "No way, Der-Pay! I'm taking it whether you like it or not!"
Twilight's horn immediately lit up as she charged up her spell she had no idea she knew up until this very split second. But, just as she finished charging, she sneezed again. And she hit right under Derpy's meat (I'm running of alternative words).
"Oh... Oh BUCK no..." Twilight mumbled, eyes widening. "This is awful.. JUST AWFUL!"
"What is it, girl?" Derpy asked. She looked down and was ecstatic. "A penis... AND A VAGINA?!"
"This is... why... I... This is... HOW!..." Twilight spluttered. "This is the worst possible thing!... DERPY, WHAT ARE YOU DOING BACK THERE?"
"Shoving a candle up your rear!" Derpy said with a smile.
"Is it lit?"
Derpy pulled out the candle quickly to check before shoving it back in. "Nope!" she replied.
"Oh, well, OK then."
Derpy nodded happily and flew off upside down to show Screwball.
"...This is the worst thing ever written," Twilight commented, addressing the fourth wall. "If you thumbs this down... It's understandable... Wait, I'm getting a message... I'm being told to shut up... Oh."
A/N: That is the worst possible thing. To make up for it, how abouts I suggest some sequels to stories in the featured box! First is I Would Smile If I Could 2: 8 Or So Years Later, in which Slenderpony gets a desk job and Scootaloo gets sent to school and it's all done like a cheesy sitcom, much in the vein of Everypony Hates Mary Sue. Hi-jinks to follow. Um, the next is Cheerisheen, which is the sequel to Lesson Plan Of A Winning Pony. Here, Cheerilee gets possessed by the spirit of Charlie Sheen. Third, there's Celestia Smokes Dust, which is the sequel to Equestria From Dust. In it, Celestia smokes dust and has her own room at the back at the bus. Finally, there's Fabulosity In Fuel, which is the sequel to Fabulousity In Fact, which is exactly how it sounds... Oh, wait, I almost forgot! Accidental OffRhythm Heaven! That's a good one!