Rainbow Dash was ready to do another Iron Pony competition with Applejack, this time agreeing to not use her wings.

It was a hot summer day rather than fall, so Rainbow Dash had a big glass of water after doing her stretches.

As usual, Twilight kept score and Spike was the announcer.

At the end of each event, Rainbow Dash and Applejack drank a mug of cider, for they were very hot and sweaty after each one.

Rainbow didn't use her wings for any of the events. They were tied by the time of the final event, which was a tug of war. After a few seconds, Applejack pulled Rainbow Dash into the mud. Rainbow Dash was disappointed, but was a good sport this time.

After drinking one last cider, she said "I should be going to the Wonderbolt show now!"

After taking a bath at home, she put on her Wonderbolt outfit and flew to the arena in Manehattan where they would be performing. Having flown very fast, she arrived early. She was thirsty after this flight on a hot day, so she drank two more glasses of water.

By the time the show was about to begin, Rainbow Dash started to feel pressure on her bladder. The cider she had drank had gone through her. But, she wasn't too concerned. She was sure she could hold it. She'd held it for a long time before. Though she hadn't had that much to drink then.

The Wonderbolts began performing with spectacular flying moves. Rainbow Dash did all of her techniques perfectly at first, although as the time went by she started to become more uncomfortable. She nearly slipped up on one move, but was able to finish the show.

Next came a race, which the rich ponies would bet on. The ponies got to the start line, and Rainbow tried not to fidget. At the sound of the horn, the Wonderbolts took off to fly around the racetrack. Rainbow Dash flew the fastest, from a combination of being the fastest pegasus and her need to pee, and won the race, to the thunderous applause of the audience.

After flying to the center of the arena and bowing to the audience, the show was over, much to Rainbow Dash's relief.

Rather than use a bathroom at the arena, Rainbow flew back to her house at top speed. By the time she was home, her Wonderbolt outfit was soaked in sweat. She peeled her outfit off and drank five glasses of water, until she was feeling cooler and less thirsty.

Yes, this seemed a foolish thing to do when she needed to pee, but she could use her bathroom now.

She had just turned in the direction of her bathroom when she caught a glimpse of a clock. It was 1:55 PM. With a jolt, she remembered that she was to fly alongside Fluttershy and Bulk Biceps in an aerial relay race at Cloudsdale in five minutes!

She quickly changed into the sports outfit Rarity had fashioned for her - a skintight pair of dark blue shorts with a white tank top. She had just reached the door when she remembered she still had to go to the bathroom. After thinking it over for a few seconds, she took off toward Cloudsdale. Surely such an awesome pony as her could hold it, plus it might make her fly faster!

She reached Cloudsdale, where Fluttershy and Bulk Biceps waited for her. They wore similar outfits of Rarity's design, except Fluttershy's shorts were green and Bulk Biceps's were gray.

"Are you ready to win the relay race?" said Fluttershy, who was confident in Rainbow Dash's speed.

"Do you have to ask?" said Rainbow Dash. She felt confident until the pressure in her bladder grew heavier, and she started to look more uncomfortable. She crossed her legs, sweating a bit.

"Oh my," said Fluttershy. "After that flight here you're probably really hot and thirsty." She quickly got Rainbow Dash a big glass of water.

Rainbow Dash was reluctant. She really needed to go, and more water wouldn't help her hold it. But, she was feeling thirsty, so she drank it without complaint.

"How much longer before the race begins?" said Rainbow Dash as she sat down, fidgeting a little.

"RIGHT NOW!" said Bulk Biceps.

Their opponents - Hoops, Score, and Dumb Bell - came in. They weren't wearing any sports outfits, and Rainbow wished at this point that Rarity hadn't insisted she and her team do so, for losing control without wearing an outfit, as embarrassing as it would be, would be preferable to if she was wearing one when it happened.

Rainbow braced herself for the jocks to notice how desperate she was and make fun of her, but they didn't. She had forgotten, they respected her now after witnessing her Sonic Rainboom.

The six pegasi got to their positions for the race. Rainbow Dash was to be the third to fly, and as soon as she reached her position, she crossed her legs, a pained expression on her face.

Bulk Biceps took a while to get to Fluttershy, and Rainbow fidgeted harder. The sooner she finished this race the sooner she could find a bathroom!

Fluttershy flew as fast as she could towards Rainbow Dash once it was her turn. She could tell how desperate Rainbow Dash was and wanted her to make it. She was dripping with sweat when she reached Rainbow Dash and gave her the horseshoe.

As she took the horseshoe, Rainbow uncrossed her legs, feeling a lot more uncomfortable. She flew as fast as her wings could carry her, reaching the finish within seconds.

"Team Rainbow wins!" said the announcer.

Rainbow Dash would normally express delight at winning a race, but she needed to pee too badly to feel anything else right now. She was about to fly off toward the bathroom, when she remembered she had to claim her trophy. Fluttershy and Bulk Biceps were already on the winners' platform, so Rainbow zipped over there, doing the pee dance. A few of the pegasi in the audience snickered, but she didn't care.

"Fluttershy, can you take the trophy?" said Rainbow Dash. "I really have to go!"

"Of course, Rainbow Dash," said Fluttershy. "Then you'll be set to race Applejack!"

Rainbow had completely forgotten that she and Applejack were going to race on a big racetrack, which took about a minute for even a fast pony like her to run a single lap. Flying would be a snap, but she promised she wouldn't use her wings. And, at Rainbow Dash's suggestion, they were to run 30 laps.

But, what was she worried about? All she had to do was use the bathroom here and she'd be fine for the entire race.

As soon as the trophy was presented to Rainbow Dash, she handed it to Fluttershy and made a break for the nearest bathroom. Rainbow could almost feel the relief already.

Until she saw ten ponies in line for the bathroom. Rainbow groaned, and put both hooves on her crotch. She could feel her desperation increase as the minutes went by, feeling like hours to her.

Somehow, each pony in front of her took at least two minutes before exiting the outhouse. Rainbow squirmed harder, and looked at the clock. It was getting close to 2:30, the time of her race with Applejack.

By the time there were three ponies in front of her, it was 2:29. Rainbow knew she'd be late for the race if she waited for the other three ponies. Letting out a frustrated yell, she took off toward the racetrack. Her desperation drove her to fly faster than she ever had before without doing a Sonic Rainboom.

She arrived at the racetrack, where Applejack was waiting. Her shorts were soaked and at first she thought she had peed herself mid-flight, until she realized it was sweat. Of course, with how much she needed to pee, if she wet herself now it would still be very noticeable.

"Ah was beginnin' to think you wouldn't show," said Applejack. "Here, have some cider."

Rainbow didn't think twice. She was so thirsty after her race and flight that she drank five cups of cider.

"That cider's real good on a hot day," said Applejack. "Course, drinkin' too much of it at once makes you gotta pee real bad. While you were doin' your Wonderbolt show I was peein' for probably close to a minute. I ain't never peed for so long, but it felt so good..."

"QUIET!" said Rainbow Dash as she leaked a bit into her shorts. But as they were already wet, this wasn't noticeable.

"Right, let's race."

Rainbow Dash and Applejack stood at the starting line, with Big McIntosh and Apple Bloom there to keep score of them, respectively, and Granny Smith as the announcer.

"Ready... get set... and go!" said Granny Smith.

Rainbow Dash and Applejack ran. Rainbow was tired from her previous competitions, but she still had to go to the bathroom really badly, and that made her run faster than she ever had in her life, desperate to finish the race and use the outhouse in the area.

Applejack was surprised as Rainbow ran by her again. And again. And again. They were usually evenly matched. Why was Rainbow suddenly faster on foot? Was she using her wings? Nope. Next time she ran by, Applejack saw clearly she was running.

As fast as she ran, the race seemed to go on forever. Her bladder was still throbbing, still more full than it had ever been. She wished she hadn't set the race to run so many laps.

"EYYYYUP!" said Big McIntosh as loud as he could, once Rainbow had crossed the finish line for the 30th time. She was exhausted, panting, and dripping with sweat, so much that if she peed right there no one would notice.

Applejack continued running for sport, waiting for Apple Bloom to signal her crossing the final time.

Rainbow Dash drank 10 mugs of cider, not caring how it would affect her later, for she could now use the outhouse. But she was so tired, she wanted to rest first. With the cool cider she drank, she stopped sweating, and before long the summer heat turned her sweaty outfit from wet to damp.

Then, just as Apple Bloom said "Applejack gets second place!", Rainbow became aware of her full bladder again. She was about to run toward the outhouse, when Applejack ran in front of her, panting and sweaty.

"Wow, you've gotten a lot faster since the last time," said Applejack.

"Well, I haven't gone to the bathroom since our Iron Pony competition and I REALLY need to go!" said Rainbow Dash.

At that moment, the train arrived at the nearby train track. "All aboard for Appleoosa," said the conductor.

"We'd better get goin'," said Applejack. "Or else we're gonna be late for our buckball game against Braeburn."

Rainbow cringed. In her desperation she had forgotten that she and Applejack were playing against Braeburn's team at Appleoosa again. Fluttershy and Pinkie Pie were better players than them, but Fluttershy didn't want to do more than one athletic event in one day, and Pinkie Pie was busy babysitting the Cake twins.

"All right, I'll be on the train in a minute," said Rainbow Dash, and she started to fly toward the outhouse, but Applejack grabbed her tail and held her back.

"We don't wanna miss the train. You can use the bathroom there."

Rainbow Dash reluctantly boarded the train with Applejack. As soon as it was in motion, she ran toward its bathroom, but to her horror it had an "Out of Order" sign on it. Rainbow rushed over to Applejack, sat down next to her, and started fidgeting hard.

"What's wrong with the bathroom?" said Applejack.

"It's out of order!" said Rainbow Dash through gritted teeth. "Why couldn't you let me use the outhouse at the racetrack and then fly to Appleoosa?"

"Cause you're exhausted from the race. You'll need to rest a bit if we're gonna beat Braeburn."

"I can't play if I have to pee this badly!"

"There'll be a bathroom there you can use, if you can hold it till then."

"And if I can't?"

"Then ah hope wet shorts won't affect your performance."

Rainbow was now wishing she had peed herself when her shorts were soaked. In minutes the sweat had completely dried off her. All the extra drinks she had taken were starting to catch up to her now. Rainbow was more desperate than she had ever been in her life. She whimpered and fidgeted hard, her legs crossed tight.

The train ride took an hour, but it felt like an eternity to Rainbow Dash, who could feel the pressure grow heavier and heavier with each passing minute. She could feel waves of pee sloshing around inside her, and wasn't sure how much longer she could hold it.

"Hang in there Rainbow Dash," said Applejack as they got closer to Appleoosa. "We're almost there."

Finally, they reached Appleoosa. As soon as they were out, Rainbow Dash ran to the nearest outhouse. It was occupied. Frantically doing the pee dance, she banged on the door, but the pony inside wouldn't come out, so she ran to the arena where they were playing buckball. This arena had a full bathroom to it, so Rainbow Dash entered it. To her dismay, every stall was full.

"OH COME ON!" she said. She felt herself leak a little, and whimpered.

Rainbow did the pee dance again as she waited for one of the ponies to get out of the stall.

"HURRY UP IN THERE!" she cried as she leaked again.

After about five minutes, the toilet flushed, and Rainbow started to feel better. At long last, she was finally going to get the relief she needed. It would feel so good to finally let it all out.

But before the stall door opened, Applejack came running in and said "Ah hope you already went to the bathroom, cause the game's startin' now!"

"Just give me one minute!" said Rainbow Dash as a pony came out of the stall whose toilet had just flushed.

"We don't have a minute," said Applejack, and she pulled Rainbow Dash into the buckball arena.

Rainbow Dash reluctantly got in position next to the basket, and the game was on.

The entire time, Rainbow had both her hooves on her crotch. Between the fact that she was hardly moving, and that a cloud had blocked the sun, cooling the weather drastically, Rainbow Dash was not sweating. The only dampness on her shorts was from when she had leaked earlier. Rainbow hoped that it would rain so that she could pee without anyone noticing, and then play seriously. However, the cloud was not a raincloud, and was the only cloud in the sky.

Rainbow was so focused on holding it that she let several goals into the basket.

"Hey, Rainbow! Try harder!" said Applejack.

"But I REALLY have to go!" said Rainbow Dash, tearing up a bit.

"If anyone can hold it and still play, it's you."

Applejack couldn't possibly understand how badly Rainbow Dash needed to pee right now. She had drank more water and cider than she would have thought possible, and was sure that it had all gone through her now. Her bladder was throbbing, and she felt like she was about to burst.

But, Applejack's words gave her the confidence to try.

She was afraid that if she stopped holding herself she'd have an accident in her shorts. So, she decided to use every other part of her to try to block the ball.

When the ball came flying toward her basket, Rainbow kicked it. This put a bit extra pressure on her, and she didn't want to kick again. The next time, she used her wing, which hurt a little from the force the ball was flying at, causing her to go off balance for a bit. Next time she saved with her head, and felt a little dizzy afterwards. Usually it wouldn't bother her, but she knew it wouldn't help her current situation.

As the ball came flying at her again, Rainbow Dash turned around and hit the ball with her butt. This sent an unexpected jolt through her bladder and she leaked for three seconds. Her shorts had a bigger wet spot on them now, and she hoped they were dark enough that ponies couldn't tell from a distance.

She let out a whimper of surprise as the ball hit her in the butt again, causing her to leak a little more.

"That tush seems to be doin' the trick," said Applejack as she kicked the ball into a basket.

"But it's making me pee a little!" said Rainbow Dash, blushing lightly.

"I'm real sorry sugarcube, but can you try to save that way for a little while longer? Ah promise you can have all the cider you want today."

"Deal!" said Rainbow Dash, though she was still in desperate need of a bathroom.

Rainbow hit the ball with her rump a few more times, still holding herself with both hooves and still extremely desperate to pee. Every few hits would make Rainbow leak a bit more into her shorts, making them wetter each time. Eventually she got so desperate she could hardly move, and missed the ball a few times. Applejack was annoyed, but seeing how desperate Rainbow Dash was, and how wet she was already, she felt sorry for her and didn't give her a hard time.

At long last, the game was over.

"Braeburn's team wins!" said the announcer.

Rainbow Dash didn't care that she had lost. All she wanted was to go to the bathroom NOW!

She ran to the arena bathroom as fast as she could, dribbling the entire way. Upon entering the bathroom, she saw that all the stalls were full, again. She frantically did the pee dance waiting for the ponies to come out.

After a five-second leak, she said "Screw it" and ran outside toward the outhouse, her shorts getting even wetter as she dribbled more.

By the time she reached the outhouse, the spurts had become a steady stream that wouldn't stop. Rainbow tried to open the outhouse door, but it was locked. At that moment, seemingly with the knowledge that she had no access to any bathrooms, she stopped holding it in and lost complete control.

Rainbow's stream grew harder as she began peeing full force. Her shorts became soaked in a matter of seconds, and her stream passed through them to the ground below her, while at the same time, rivers of pee flowed down her legs in torrents. A massive puddle grew under her.

Rainbow couldn't believe what was happening. She, the fastest flyer in all of Equestria, one of the Wonderbolts, and one of the saviors of Equestria, was wetting herself uncontrollably. Ponies were staring at her, and she blushed with embarrassment, all too aware of the hissing sound emanating from her and the rapidly expanding puddle she was standing in.

She couldn't stand anymore, and sat down, her rear end splashing into her puddle, and still peeing. As humiliating as this was, she couldn't deny the relief felt really good after holding so much in for so long. The warm wetness that soaked her lower half also felt good too. Almost... arousing.

"Ahhhhhh, that's better," said Rainbow Dash, still peeing.

Applejack ran over to Rainbow Dash, stepping in her puddle, backing away, and staring at the pegasus as she continued to soak herself, blushing but looking as though she was enjoying it. She felt bad for Rainbow Dash, and wished she had let her go before the game, delaying the game just a minute to spare Rainbow Dash total humiliation. Except... Dashie looked like she was having fun wetting herself.

She peed for just under three minutes, at the end of which she was sitting in a huge puddle and her cute skintight shorts were completely drenched. She let out an immense sigh of relief now that her bladder was completely empty. Then the realization that she had peed herself in front of several ponies, including Applejack, hit her, and she blushed beet red.

"It's all right Rainbow Dash," said Applejack, and she helped the pee-soaked mare get to her feet. "Let's get you home."

They boarded the train that went back to Ponyville. There were no other ponies in the car. Rainbow Dash sat in her wet shorts, still feeling ashamed.

"I'm sorry ah wouldn't let you go before," said Applejack.

"It's all right," said Rainbow Dash. She was still embarrassed, but she had secretly enjoyed the feeling of peeing herself, and now she knew Applejack wouldn't think any less of her for it.

"Remember our deal. You can have all the cider you want today."

Rainbow Dash was feeling much better already.

When they reached Ponyville, Rainbow Dash flew high in the air to Sweet Apple Acres, avoiding being seen. Afterward, she drank 20 cups of cider.

When Rainbow returned to her house, she felt she needed to pee again. Though not nearly as badly as last time, she sat on the toilet, without pulling her shorts down, and began peeing.