Author's Notes:

This chapter is in two parts, one in Equestria Girls and one in Equestria.

In the Equestria Girls world, Fleur de Lis was doing some modelling in a beautiful purple dress.

She had just stepped onto the outdoor stage when she felt a stomach cramp, and could hear a gurgling sound. She let out a silent fart and started posing for the cameras.

As she posed, she could feel the pressure in her bowels increase. She wished she had used the bathroom before she left, but she hadn't needed to go then. Being a supermodel, she really hated having to poop this badly.

Her next position involved bending over, and as she did, she accidentally farted very loudly.

PPPPPPFFFFFFFT!

She blushed while the audience gave a mixed reaction of laughter and disgust. But she continued to pose, as though nothing had happened.

She farted several more times, each wetter and stinkier than the last.

"Do you need to use the bathroom?" said Hoity Toity. "We can wait."

Fleur de Lis was grateful for this. She ran to the bathroom door, but there was a bit of a line. She held it desperately, farting several more times.

Rarity and Pinkie Pie were also in line. Rarity was holding herself, indicating she needed to pee, while Pinkie Pie was farting as loud and wet as Fleur de Lis was, indicating she needed to poop as well. One particularly wet fart left a small brown stain on her shorts.

However, Pinkie was next in line. She ran into the bathroom and closed the door. Loud fart sounds and splashing could be heard on the other side, which made Fleur uncomfortable. Rarity would have been disgusted, but she was too desperate to pee to pay much attention. Fleur let out another wet fart, and her pink panties seemed to feel a little dirtier than before.

Just as Pinkie exited the bathroom, Fleur couldn't hold it anymore. A wave of diarrhea burst out of her rear, soiling her panties and flowing down her back legs. Diarrhea turned into hyperscat, filling her underwear with a wet, brown, smelly mess.

She blushed profusely and ran toward the nearest bush, hoping to hide her accident from as many people as possible. As she ran, she let out a sloppy wet fart, releasing a little more scat into her panties.

She reached the bushes, pulled her heavily soiled panties down, and threw them away. She wiped herself using leaves. She had to use a lot because she didn't just have to clean her butt, but her legs as well. When she was done, she was sure she'd have to wipe her butt a few more times, but that could wait, besides, there was a brown stain on the butt of her dress too.

She sheepishly walked back onstage. "Um... Is it all right if we do this shoot another time? I don't think I can do it today."

"We understand," said Hoity Toity. "And I do hope that stain comes out."

Fleur blushed and ran home, hoping no one else noticed the stain on her butt.

As she ran, the second wave struck. The pressure in her bowels indicated more diarrhea. She didn't want to soil herself again. It would make more of a mess since she wasn't wearing panties anymore.

After lots of running (and wet farts), she reached her house, frantically unlocked the door, ran into the bathroom, hiked up her dress, sat on the toilet, and let go.

She sighed in relief as the diarrhea splashed into the toilet. The relief felt so good. And sure, she had messed herself once today, but not twice.

About a minute later, she was done. Her toilet was nearly overflowing. She'd need a plumber to fix this.

But first she took a nice hot shower and changed into a clean dress.

...

Equestria's Fleur de Lis was taking a holiday on the beach, wearing only a hat and sunglasses. Rainbow Dash and Applejack were playing beach volleyball nearby.

She was relaxing in the sun when suddenly a familiar and unpleasant feeling hit her. Her stomach was gurgling and she felt an intense pressure in her bowels.

She let out a silent fart, relieved that no one heard it. Her next fart, however, was louder and deeper-pitched.

BBBBBBBRRRRRRRRT!

She blushed, but fortunately no ponies were close enough to hear her. Rainbow Dash and Applejack were closest and they were too focused on their game to notice any fart sounds. Lucky for her, because Rainbow Dash would likely laugh, as she had that time Rarity farted when both she and Fleur were around.

After a few more wet farts, she knew she had to do more, and ran to the outhouse. She groaned when she saw an Out of Order sign on it, farting again as she did so.

There was only one other option. She ran toward the forest, which was quite a ways away.

As she ran, her farts became wetter, and she was afraid she'd leave a mess behind her soon. Like her human counterpart she really hated having diarrhea or hyperscat.

After a run that seemed to take forever, she reached the forest, got behind the nearest bush, and released the contents of her bowels. After about half a minute, there was a huge pile of hyperscat behind her. She blushed at the idea that someone might eventually find it, but she was feeling relieved that she hadn't taken a dump in front of other ponies. More so that she hadn't been wearing any panties, shorts, or jumpsuits to soil.

After wiping herself with some leaves, she decided to go straight back to the hotel.

Much like her human counterpart, it was then that the second wave struck. She ran faster, farting the entire way.

She finally managed to reach her hotel room with nothing but farts coming out of her butt. She ran into her bathroom, not bothering to lock the door, sat on her toilet, and let projectile diarrhea explode out of her rear.

Again, it lasted about a minute, but she finally finished. Her toilet was nearly overflowing. She'd have to call the hotel staff to get it fixed.

She had just stood up when she let out one last fart, and more diarrhea flowed down her back legs. She moaned and started to clean herself up.