Author's Notes:

Pinkie Pie treats Rainbow Dash and Rarity to a big lunch, and then they hang out at the beach, before going for a walk in the nearby woods. However, something in their meal did not agree with them, initially causing a major gas attack, but soon causing them to have to poop faster than they should have. Will any of them make it? Who will last the longest?

Note: This is the Equestria Girls Rainbow, Pinkie, and Rarity, not the ponies.

One summer day, Pinkie Pie invited Rainbow Dash and Rarity to her house. Due to the hot weather, Pinkie Pie was wearing short jean shorts, and Rarity was wearing cute purple shorts the same length. Rainbow Dash was wearing her usual skirt with skintight black shorts underneath.

Twilight, Sunset, Applejack and Fluttershy were busy today, so they couldn't come.

Pinkie cooked an extremely big lunch for them. It consisted of apples, bananas, potatoes, prunes, oatmeal, and a massive bowl of brown beans. They each had a big glass of chocolate milk as well, emptying the milk carton she had just picked up, whose expiry date was several months ago.

All three girls found every food item to be extremely delicious, and devoured it all within fifteen minutes, despite the fact that Pinkie had overestimated how much she would need. They were absolutely stuffed, and downed their glasses of chocolate milk immediately.

"Hey, wanna go to the beach?" said Rainbow Dash once they were done.

"That sounds smashing," said Rarity.

So the three girls walked all the way down to the beach, enjoying the summer weather. Once there, they relaxed in the sun for about a half hour, by which time the food had settled.

"Wanna go for a walk in the woods over there?" said Rainbow Dash.

"Sure!" said Pinkie.

"I suppose some shade would be nice," said Rarity.

So, Rainbow, Rarity, and Pinkie got up and walked down the path through the woods. The shade did feel nice after laying in the hot sun for so long.

"Hey, race you to the other end of these woods!" said Rainbow Dash, and she ran.

"No fair, you got a headstart!" said Pinkie, and she zipped after Rainbow.

Rarity ran, not caring whether she won, but she would have fun nonetheless.

Rainbow was more than halfway along the long path when she felt her stomach cramp, and slowed down.

Pinkie ran by Rainbow. "I'm winning now!" she said, slapping her butt in a taunting way.

Rainbow picked up the pace, but Pinkie also felt a stomach cramp, and slowed down, allowing Rainbow to take the lead again.

Rarity ran at a steady pace. She felt a gurgling in her stomach, which puzzled her because she had just eaten. She reached the end of the forest to find Rainbow Dash and Pinkie Pie already there.

"I won," said Rainbow Dash. Pinkie nodded her head.

"That was, rather fun," said Rarity, panting. Her stomach gurgled again.

"I think we ran too fast after eating," said Rainbow Dash. "My stomach's cramping up."

"Me too," said Pinkie. "Let's head back.

As they turned around, Pinkie felt a gurgling inside her as well.

They had barely walked for ten seconds when...

PPPPPPPPFFFFFFFT!

Pinkie Pie giggled at the sound that had come out of her. Rainbow Dash also laughed.

"Pinkie Pie!" said Rarity. "That's so unladylike!"

"Lighten up, Rares," said Rainbow Dash, and she lifted her leg and let out a loud wet fart of her own. Pinkie laughed even harder and farted again.

"You're both absolutely disgusting," said Rarity, wrinkling her nose at the stench. "Really, I don't..."

PPPPPPPPRRRRRRRRRRT!

Rarity blushed.

"Now who's being unladylike?" said Rainbow Dash, snickering as she farted loud and wet again.

"Ugh, fine. Pinkie Pie, something in your meal was just... not right."

"That's probably the beans," said Pinkie Pie. She paused to fart again. "They make you more gassy than anything else can!" She farted again for about six seconds.

Rainbow Dash laughed, and farted for seven seconds, louder and wetter than Pinkie.

"That's it, I am never..." PPPPPPPPFFFFFRRRRRRT! "...having beans again!"

"Are you gonna tell me this is the first time you've ever farted?" said Rainbow Dash.

"Well... no, but I always do... that... silently, away from anyone else, and never this much!" Rarity let out a loud, wet fart that was only one second long, and tried to fan the smell away with her hand.

PPFFFFT! FFFFFRRRT! BRRRT! PPPRRRRT!

Pinkie giggled with each loud wet fart that came out of her rear.

BBBBBBRRRRRAAAAAAAAP!

Rainbow Dash laughed at her own deep-pitched fart.

Rarity tried to fart silently, but her next fart came out louder and wetter than before, and lasted eight seconds, much to her dismay, and Pinkie and Rainbow's amusement.

"Seriously, nothing should be able to make you... break wind... this much!" said Rarity.

"It does for me!" said Pinkie, and she lifted her leg again.

BBBBBBBBBBRRRRRRRRRT!

This fart was a lot wetter, and Pinkie stopped laughing. She put her hands on her butt, afraid that she had made a mess in her shorts. She saw that this was not the case, but the butt of her shorts did feel wetter than before. Although she did not know it, her white panties had a small brown stain on them.

Rainbow Dash and Rarity let out similar farts, and also found their panties to be a little wet. These farts also smelled worse than their previous ones.

"I... think something we ate didn't quite settle well with us," said Rarity.

"It couldn't have been anything we ate at my house!" said Pinkie. "Although... the chocolate milk did taste kinda funny."

"Did you check the expiration date on it?" said Rainbow Dash.

Pinkie Pie giggled sheepishly, letting out another wet fart.

It was then, that the pressure started to build up. Rainbow Dash, Rarity, and Pinkie Pie needed to poop, and they all knew the need would increase, fast.

"We have to get to a bathroom right now!" said Rainbow Dash, farting loudly.

"But the nearest bathroom is at the beach!" said Pinkie Pie.

"Then let's not waste any time getting there," said Rarity.

They ran for about 30 seconds, but their stomachs started cramping up again, so they stopped, and walked the rest of the way.

"We might have to fart to relieve a bit of pressure," said Rainbow Dash, and she farted loud and wet.

Pinkie Pie quickly farted again, even wetter, giggling at her flatulence.

Rarity sighed, and farted even wetter than Pinkie, blushing lightly.

BBBBBBRRRRAAAAP!

PPPPPPFFFFFFFFFFT!

FFFFFFFFFRRRRRRRT!

Rainbow chuckled even though she could feel her panties get dirtier. Pinkie giggled as well. Rarity put her hand on her butt, dismayed to discover her panties felt dirtier than before, although there was still no mess inside them.

Over the next five minutes, they farted some more, and as they did, their underwear became dirtier and wetter, though they still avoided actually soiling themselves. They felt more desperate by the minute. As time went by each fart became wetter and smellier.

Rainbow lifted her leg and let out a boisterous fart.

Pinkie giggled, and then farted again.

PPPPPPPPPBBBBBBBBBBBLLLLLLLLLLLSSSSSH!

Pinkie froze in her tracks as she released a very wet brown mess into her shorts, which turned brown at the back. After soiling herself for nine seconds, she blushed and giggled sheepishly.

"Ugh," said Rarity in disgust as the stench reached her nostrils.

"I need to go change," said Pinkie, feeling embarrassed.

"We have to find a bathroom first!" said Rainbow Dash, who could feel the pressure growing heavier.

They walked. Pinkie was uncomfortable at first walking in her messy shorts, but after a while, she began to like it.

As Rainbow Dash and Rarity continued to walk by, Pinkie sat down, feeling her wet mess squish beneath her rear, and how she enjoyed the sensation, giggling as she squirmed slightly.

"Pinkie, that's absolutely revolting!" said Rarity. She felt another loud fart make its way out of her butt, and knew she couldn't hold it much longer. "Uhhhh... I can't hold it!"

Rarity ran behind a tree. Pinkie remained sitting where she was, while Rainbow moaned in discomfort, not even bothering to laugh as she farted again. Even if she made it she'd have to change her underwear as soon as possible.

Rarity pulled her shorts and panties down, squatted behind the tree, and released the contents of her bowels very loudly. She blushed, but felt better about it, and at least she hadn't ended up like Pinkie Pie.

She finished, pulled up her shorts, and looked in disgust at the big pile of crap she had made on the ground. She was even more disgusted by the state her panties were in, even though she had avoided a full-blown accident.

She was just rejoining Rainbow and Pinkie, when...

PPPPPPBBBBBBBBBTTTTTTTTTTHHHH!

Rarity blushed beet red as a loud, wet, smelly mess burst out of her rear and into her shorts. It seemed that her bowels weren't completely empty after all, unfortunately for her.

Pinkie Pie giggled, but Rainbow Dash was in too much pain to find anything funny at the moment.

They continued their walk toward the beach, Pinkie looking as though she had sat in a mud puddle, and Rarity feeling very uncomfortable with the muddy mess in her shorts, not to mention the smell. Naturally, she also felt ashamed. This was so undignified.

Rainbow Dash farted several times along the way, at one point releasing a fart so wet and so boisterous she stopped to put her hands on her butt, and although there was still no mess, the back of her shorts felt very wet now. She needed to get to a bathroom fast!

It wasn't long before Pinkie started farting again. As they reached the edge of the forest, in view of the beach, Pinkie felt she needed to go again. This time she just pushed it all out into her shorts, again rather noisily, giggling the whole time.

"Pinkie, did you just soil yourself again?" said Rarity.

"My shorts are already messy, so why bother?" said Pinkie unabashedly.

As soon as Rainbow had the bathroom in her sights, she ran as fast as she could. Her stomach cramped a bit but she didn't care. She farted a few times, each fart wetter than the last, but she was so close!

She reached the bathroom... and it had an Out of Order sign on it.

There were two more bathrooms in the area. Rainbow checked one, but the toilet was clogged. She tried to open the other, but it was locked. Someone was inside. Rainbow waited impatiently in front of the door. She was this close to finding relief, but she knew she was just as close, possibly closer, to having an accident.

Then, Sonata Dusk came out, looking rather sheepish, and walked away.

Rainbow quickly entered the bathroom, but to her dismay its toilet was clogged as well. Sonata must have done this. The sight of this seemed to force her to let go.

BBBBBBRRRRRAAAPPPPPFFFRRRRTTTTTLLLSSSSSSHHHHHPPPP!

Rainbow blushed as she felt her shorts filling up with a warm, wet, muddy mess. She could smell it in a matter of seconds, and moaned in embarrassment.

She messed herself for 16 seconds, and then sheepishly walked outside in her soiled shorts.

"Well?" said Pinkie.

"I didn't make it," Rainbow said, blushing. "The toilet was clogged."

"It's no big deal!" said Pinkie. "Sit down. It feels really good, trust me."

Rainbow sat down, and felt the squishing under her tush. It felt weird at first, but after moving around for a bit, she realized she enjoyed it, and laughed a little.

"Seriously, why would you two even..." began Rarity, but Pinkie quickly got her into sitting position. Rarity yelped at the squishy feeling, but had to admit part of her did seem to think it felt rather nice. She was disgusted at herself for even thinking this. The state she was in alone was so unladylike, and this was a lot messier than sitting in a mud puddle.

Then, all three girls farted again at the same time. Their farts were very boisterous, very long, and very wet.

PPPPPPPFFFFFFFFFFRRRRRRRRBBBBBBBLLLLLLLLRRRRRRRRRRRRRRTTTT!

About two seconds into the simultaneous farts, Rainbow, Rarity, and Pinkie messed themselves again.