Sunset's M-ASS-IVE discovery

by WinterFang

Rating: mature
Tags: Sunset Shimmer, Main 7 (EqG), Random, Slice of Life, Fetish, Equestria Girls, Sex
Length: 4188

Sunset Shimmer's butt becomes enormous

During a camping trip, Sunset shimmer come across something that becomes a huge pain in the ass.

story contains: [ass expansion/ ass play]

Published 2022-09-11 16:20:00 UTC
Last updated 2024-08-03 05:47:40 UTC

2

Early the next morning, Sunset awoke to the feeling of her pajama pants somewhat tighter than normal. She soon discovered the reason as she changed clothes. Sunset's ass had somehow nearly doubled in size. The discovery almost made Sunset scream out of fear at the sight. Sunset was trying to think of a way to explain when she heard Applejack calling her from outside her tent.

"Hey, Sunset? You up yet sugarcube?"

"Y-Yeah, I'm up. I'll be there in a minute." replied Sunset.

"Alright. We'll be waiting then"

As Applejack left to rejoin the others, Sunset frantically looked through her clothes to see what could fit her new size. She quickly came across a pair of pants that seemed like they had just enough elasticity to cover her bigger assets. Sunset was somewhat relieved to discover that her panties still fit to a point before she attempted to put on her pants. It took her several attempts, but Sunset eventually got her pants before turning her attention to finish getting dressed. Once she had the rest of her clothes on, Sunset left her tent hoping that no one noticed her butt increased size.

"There you are darling. We were wondering what was taking you so long." said Rarity

"Sorry. I had some difficulties with what to wear today." replied Sunset.

"Your outfit looks good. Although, something seems different about you today.” said Rarity taking a good look at Sunset.

"Who cares? She's here now, let's just get on with our day. Right Sunset?" interjected Rainbow slapping Sunset on the ass, before heading to the nearby nature trail.

The sensation of Rainbow Dash smacking her ass sent a wave of pleasure through Sunset's body. She did her best to hide the fact that she liked it, but a small blush found its way onto her checks. Fortunately, the others had started to follow Rainbow Dash to the trail. The girls spent most of their day traveling down an old nature trail that is somewhat difficult for Sunset since her new size meant that she was slightly slower than her friends. On top of that, Sunset was also trying not to rip open a hole in her pants. Sunset's slower pace was soon noticed by Pinkie Pie.

"Hey. Why are you walking so slow, Sunny?" asked the party planner using her nickname for Sunset.

"Oh. I'm just enjoying the scenery is all." replied Sunset still worried about new enhancement getting spotted.

"Yeah. This place is pretty nice. A place like this can really grow on you.” said Pinkie as she looked around

Sunset felt the same tingling sensation in her ass as last night. The only difference was that the sensation felt stronger than last time. Luckily, Pinkie was still looking at their surroundings to notice a small shiver run up Sunset's spine. As the two girls continued talking about different things, Sunset couldn't help but notice that her pants were getting even tighter. The tightness only grew until *RIIIIIP*. A loud tearing sounded through the area causing everyone to look at Sunset, whose face had turned a deep shade of red. Her pants had torn completely to reveal her butt's new size. Sunset just stood there in silence for a few moments out of complete embarrassment while the others merely stared. The tension was broken when Rarity asked the question that was on the group's mind.

"What on earth happened to you, Sunset?"

"In all honesty, I don't know. I woke up this morning and noticed that my ass had gotten bigger." replied Sunset.

"Do you have any idea how this could have happened?" asked Twilight.

"Not really. Nothing like this has happened to me before."

"I wonder what could cause it. I mean, no one's rear end just growing for no reason." Said Applejack.

"As much as I would like to continue this conversation here, maybe we can finish it back at the campsite?" suggested Sunset.

The others agreed since none of them wanted any surprised guests dropping on them out of nowhere. The walk back took longer due to Sunset's ass being four times its size from yesterday. It also didn't help that Rainbow Dash and Pinkie Pie kept trying to play her butt every chance they got. Eventually, the group managed to return to their campsite safely and started trying to figure out how Sunset's rear end got so big. They eventually came to the conclusion that it was the pendant that Sunset discovered last night. The next question they had on their minds was, what caused the pendant to make Sunset's butt bigger.

"It could be a word or a phrase." said Twilight.

"The only problem is that, we don't know what it could be."

"That's not completely true, darling. I have a feeling that whatever the trigger is, it's very specific. Otherwise, your backside would be continuing growing right now." said Rarity.

"You make a good point, Rarity. In the meantime, I need to return to my tent. All this cool air feels weird on my ass." said Sunset getting back to her feet with some difficulties and made her way to her tent.

Sunset could feel her friends staring at her enlarged butt as she walked the short distance to her tent. She could feel it bounce slightly with each step. Once back in her tent, Sunset went over each time her back side had expanded to see if she could figure out what caused the growth. Unfortunately, Sunset just couldn't think of any specific word that would make her ass this huge. She pulled out the pendant from her shirt to get another look at the picture on it.

"Hard to believe that all of this comes from something ordinary. I wonder what word triggers this thing to make my ass grow.” said Sunset laying down on her stomach.

Once again, Sunset felt that tingling sensation in her rear end that sent a stronger shiver up her back. The sensation had also gotten even stronger as well. Sunset also noticed that the pendant was glowing. It was at this realization that Sunset knew what the trigger word was. Her theory was soon proven correct moments later as her butt grew to the point where it could match a yoga ball in size. Sunset was both relieved and nervous at the discovery of what the trigger word was. Sunset felt that it would be better to wait until tomorrow to tell her friends about what she had found out. Sunset spent the rest of the day getting used to the new weight of her ass.

3

The following morning, Sunset was awoken by something pressing against and into her ass repeatedly. She tried to brush it away and get back to sleep. However, the sensation merely slowed down but didn't fully stop. What caught her attention was the voices she heard that caused her to fully wake up.

" I told you you were going too far, Pinkie. Now, she's probably going to wake up." said Rainbow Dash.

"Sorry, Dashie. I just lost myself in this fine ass." replied Pinkie.

"Thanks for the compliment, Pinkie Pie. Now, can you please let go of my ass?" asked Sunset as she tried to look over her enlarged backside.

When she could finally see over her huge butt, Sunset was surprised to see not only Pinkie and Rainbow. But also Twilight and Fluttershy were in her tent. Upon spotting Twilight, Sunset could guess how they got into her tent.

"Do I even want to know why you four are in my tent? Besides playing with my butt?"

"Well, Fluttershy and I wanted to see if you had figured out about your recent growth spurt. As for Rainbow and Pinkie, they ARE just here to play with your booty." replied Twilight.

"I can see that, and yes, I have figured out the reason for my size. I can tell all of you OUTSIDE once I can find something to wear." said Sunset.

Rainbow looked like she was about to say something, but Sunset gave her a glare that stopped Rainbow in her tracks. Once the others had left, Sunset looked over her stuff to see what she put together to cover her enormous ass. The only thing that looked like it could come close to covering up her larger lower half was the towel that she had brought. Unfortunately, Sunset's towel wasn't as big as she had thought. While the towel did reach around her waist, Sunset quickly realized that she was unable to tie her makeshift skirt. She tried to look for something to add to the towel, but nothing seemed to help. Sunset spent another two to three minutes trying to get the towel to work, but she ultimately gave up and just put on a clean bra and shirt. Once dressed to the best of her abilities, Sunset moved to leave her tent with some difficulties to meet up with the others.

"You took your sweet giant ass time." said Rainbow Dash with a joking smirk on her face.

"Please be serious, Rainbow. She does somewhat of a point, Sunset. You did take quite a bit of time getting ready, such as it is." said Rarity, looking over Sunset's half-dressed appearance.

Sunset decided to ignore the remark and told her friends what she had discovered last night. Although, she was careful not to say the trigger word out loud. This didn't go unnoticed by the other girls.

"Before any of you ask, no. I'm not going to say what the trigger word is. My butt is already big enough.". said Sunset in response to the questioning looks on her friend's faces.

"That seems fair. Don't want any unnecessary extra growth."

"In that case, perhaps it would be better if you wrote it." suggested Fluttershy.

No one else seemed to have any other ideas, so Sunset got a piece of paper and a pencil to write down the trigger word. But, on the condition that no one says it out loud. Sunset was glad to find that writing down the word didn't activate the pendant.

"Really? That's the word to make your rear end bigger?" asked Rarity

"So. I'm more curious about why this word is so specific. It seems rather risky to have such a common word be the trigger. All it would take is someone slipping up, and my butt would get bigger again."

"Don't worry, Sunset. All of us will make sure to watch what we say around that pendant of yours. Right, girls?" said Applejack eyeing Rainbow Dash and Pinkie as she said the last part.

Rainbow and Pinkie promised to do their best as did the others. After that, the group tried to think of what to do that day. Fluttershy had suggested another nature walk but was quickly shot down due to not wanting anyone to see Sunset's new size. They continued to think until Applejack suggested that they go swimming. The others agreed, and Twilight mentioned that there was a lake nearby. They all went to change into their swimsuits, save for Sunset. Fluttershy noticed this and walked over to her.

"What's the matter, Sunset? Aren't you going to change into your swimsuit?"

"I don't think so. It had occurred to me that my swimsuit might not fit my new size." said Sunset, glancing at her enlarged butt.

"Will you at least tag along?" asked Fluttershy

Sunset nodded in agreement and said that she would wait for the others. Fortunately, she didn't have to wait very long for the others to change. They soon departed for the lake that Twilight mentioned after Sunset explained why she didn't put her swimsuit on. Applejack reassured Sunset that it was fine and offered to help her to the lake.

"Thanks, Applejack. This thing has been getting really heavy." said Sunset

"I'll bet." replied Applejack with a small chuckle.

To Sunset's surprise and embarrassment, Applejack told her to climb onto her back. Sunset asked if it was okay for her to ride on Applejack's back. The farm girl reassured her that it was just fine. Sunset was still a little nervous about the situation. Especially when it seems that Rainbow Dash and Pinkie Pie couldn't keep their hands to themselves. She ultimately decided to take Applejack up on her offer and climbed awkwardly onto her back. Once Sunset was on Applejack's back, the group made their way to the lake. Sunset still felt kind of awkward about being carried like a kid. However, she was thankful to have such caring friends by her side to help with her current situation. The group soon got to the lake and were in awe at the sight of it. The lake was larger than normal, but it wasn't huge, and it was the textbook definition of crystal clean.

"This place is amazing, Twilight." said Rainbow Dash

"Indeed. I've never seen a place so wonderful." said Rarity in agreement.

"I know what you mean. I felt the same way when I first came here."

"I can see why. This is a great place to grow closer together" said Fluttershy, not realizing that she accidentally said the trigger word.

Sunset Shimmer gripped Applejack's shoulder tighter as she felt the familiar sensation course through her body stronger than ever.

"You, alright there, sugarcube?"

"Yeah. Fluttershy just accidentally said the trigger word is all." replied Sunset.

"Oh my. I'm so sorry, Sunset. I didn't mean to say it." said Fluttershy apologetically as Applejack placed Sunset down.

"It's okay. I know you didn't mean it." replied Sunset as her ass got bigger.

By the time her latest growth spurt was over, Sunset's butt was about half the size of her tent. It has also become far more senative due to the new size. So after Sunset was settled underneath a nearby tree, the girls spent most of the day swimming in the lake. Sunset was able to get some swimming in, but due to her enormous ass, she couldn't swim for too long. The group eventually made their way back to the campsite as the sun began its descent.

"That was awesome." said Rainbow Dash as they entered the campsite.

"Indeed. that was lots of fun." said Rarity in agreement.

Wen gotta go back the next time we're here."

"Absolutely. The lake is a great hangout while camping out here." said Twilight.

As the other girls changed back into normal clothes, Sunset went into her own tent and pulled out the journal that links her to Equestria. She went on to write to Princess Twilight about how she found a strange pendant while on the first night of a week long camping trip with her friends. Ever since then, whenever someone says the word Grow, her ass would get bigger. Sunset also mentioned that writing down the trigger word won't activate it.

"I was wondering if you knew of any such items in Equestria that might have similar abilities. It's going to be a while before we can meet at the portal since my friends and I plan to stay at our current campsite for another four days. I'll write again if anything else happens." concluded Sunset as she set down her pen. Once she had managed to crawl her way out of her tent, Sunset spotted Rarity coming out of her tent.

The two girls began talking about what they thought about the trip so far. This caused Sunset to apologize due to her ass forcing them to readjust any plans they might have had. Rarity reassured her friend that what happened to her rear-end was an accident and could have happened to any of them and the rest would not hold it against her. A sentiment that was echoed by Applejack as the others exited from their tents. The farm girl backed up Raity's earlier statement that what happened to her was a complete accident and if she could trade places with Sunset, she would. The other four agreed that they would do the same. All of this encouragement brought tears of joy to Sunset's eyes. She thanked her friends for everything and mentioned that she wrote to Princess Twilight Sparkle and was waiting for a reply. Rainbow Dash asked how it was going to take. Sunset simply said that she was unsure but hoped that the other Twilight would get back to her soon. For the rest of the day, the group of friends sat around the campfire swapping stories, their dreams for the future and making s'mores. Eventually, the girls decided to call it a night and head to bed.

4

The following morning, Sunset awoke to the sound of a light buzzing sound. She soon realized that it was her journal making the noise. With some difficulties, Sunset was able to reach her journal to read Princess Twilight's response.

"Dear Sunset Shimmer,
I have some news about that pendant you told me last night. Apparently, it belonged to a powerful unicorn mare who has a strange idea of beauty. The pendant was last to be created that would enhance a physical trait of the wearer. Unfortunately, any more information is non-existent since the mare scattered her creations before Star Swirl and the other pillars could get to them. I'll try to do more research and hopefully come up with a way to reverse the effects.

Your friend, Princess Twilight Sparkle.

"Well, that's fantastic." said Sunset to herself as closed the journal.

After a bit of trouble getting ready and out of her tent, Sunset made her way to the campfire, where the rest of her friends were waiting. Once she got there, Sunset told her friends what just learned Princess Twilight.

"So, let me get this straight. An extremely powerful unicorn made several items that can cause physical changes due to that unicorn's lust for beauty. And after a thousand years, you just so happened to find the one that makes the wearer's ass bigger by simply saying the word grow?" inquired Rainbow, even knowingly saying the trigger word.

"That's the long and short of it." said Sunset as she felt the familiar sensaton run through her ass once again.

"What does it feel like when that happens." asked Twilight.

"It's kind of hard to explain. The best way to explain it is like getting into the world's best hot tub. As for the
actual growth. It just feels like someone is gently pushing against the inside of my buttcheeks." replied Sunset as her ass finished growing to the size of her tent.

"That's a rather odd sensation."

"You can say that again. And don't even get me started on the weight." added Sunset.

After a couple more minutes of discussing Sunset's enlarged ass, the conversation soon turned to what they were going that day. Fluttershy suggested trying to go on a hike again. Before the others could say anything, Fluttershy reasoned that they haven't seen anyone else while they've been there. And most likely won't run into anyone for the remainder of their trip. The others were surprised slightly at Fluttershy's logic. The group made their way to the previous hiking trail and were able to complete it. Sunset did find the trail difficult due to her huge backside. She only managed to get through it thanks to her friends. For the remainder of the trip, the girls spent their time sitting around the campfire talking about various topics and did several more camping activities. By the time their trip came to an end, Sunset's ass had grown to roughly half the size of the van they used to get to the camp grounds, thanks to Rarity and Twilight saying the trigger word.

When the time came for them to head, the group tried to come up with solutions to get Sunset back home. One suggestion was to put their stuff in the van and have Sunset ride on the roof. But that one got rejected for several obvious reasons. They settled on the idea of just folding the seats into their compartment and hoping that would give them enough room. Despite the tight fit , thanks to Sunset's voluptuous cheeks, the group managed to return home by early evening. Upon entering her apartment, sunset was able to write to Princess Twilight. Letting her know that she and her friends had gotten back from their trip and will be able to meet up at the portal the following day. When the group did meet with Princess Twilight, she sadly informed them that she and the other Princesses couldn't find any way to turn Sunset back to normal. She wasn't even sure that taking the pendant back to Equestria would help the situation. Sunset already had a bit of a feeling that would be the case, but she felt bummed out at the news. Seeing this, Princess Twilight and that she would be staying for a couple of days to help Sunset and to have a chance to study the pendant.

1

"And we're finally here." said Twilight setting down her backpack.

"It's about time. It feels like we've been walking forever." said Rarity following Twilight's lead.

While taking a break to catch their breathe, Applejack turned to Twilight and asked "By the way Twilight, how did you find this place?"

"It's an old camp ground my parents would take my brother and I when we were kids. Not a lot of people know about this place, so I thought it would a good place to spent our Spring Break. answered Twilight.

Once they had regained some of their strength, the girls started to setup their campsite. Sunset volunteered to go fetch some firewood for that night. As she looked for good pieces of wood, Sunset came across an odd pendant. Curiosity had got the best of the former pony, and she picked up the pendant.

"What in the world is this?" asked Sunset.

Upon closer inspection, Sunset noticed that the pendant had an ornate depiction of a woman with an enlarged backside. This only increased the young girl's curiosity to the point where, she placed it around her neck before she continued with her task. Sunset soon returned to the campsite with a good amount of wood in her arms and soon the girls had a roaring fire. As the girls were in the middle of making S'mores, when Rainbow Dash noticed the pendant that Sunset had.

”Hey cool pendant, Sunset. Where did you find it?"

"Oh this? I found it when I was gathering firewood earlier." replied Sunset lifting it slightly to give the others a better look.

”Oh my. I've never seen anything with a unique design on it." said Fluttershy blushing as she indicated to the large ass woman.

"I know what you mean. It caught me off guard when I found it, but it's starting to grow on me." said Sunset looking back down at the pendant.

At the word grow, Sunset felt a tingling sensation in her own rear end that lasted only a few seconds before fading.

"Sunset? Are you okay darling?" asked Rarity seeing the odd expression on her face.

"Y-Yeah. I'm just a little tired is all. I think go to bed early.” replied Sunset as she headed to tent.

As she got ready for bed, Sunset felt like her ass was somehow bigger then it was moments ago. She quickly shook the notion from head and got into her sleeping bag and soon fell asleep, unaware that the pendant had started giving off a soft light.

Epilogue

*SIX MONTHS LATER*

"Morning, Sunset. How are you doing today?" asked Applejack as she entered her family's barn.

"So far, so good. I would be better if I could still walk." said Sunset looking at her enormous ass.

Sunset's backside had grown to a point where the only place she could easily fit, was the Apple family barn, due to some of the other students accidentally saying the trigger word. On the upside, her new size allowed Rarity to create a line of clothes for people with enlarged features.

”Do you need anything before I leave?”

"I'm good for now,but thanks anyways."

"Alright then. Oh. Before I forget, Rarity just called saying that she'll drop by with some new undergarments for you." said Applejack as she made her way to the door.

"That's good to hear. I hope the others get to drop soon." replied Sunset.

"I'll let the others know you said that. See ya after school, Sunset." said Applejack.

Sunset leaned back on her rump and softly smiled to herself.

"I'm so glad that I have great friends to rely on. Hopefully, we continue to grow closer in the future. said Sunset accidentally saying the trigger word.

Sunset only realized her mistake when she felt the familiar process of her ass getting bigger. By the time it was done, Sunset's rear end was gently pressing against the barn's walls.

"For the love of Celestia. This is going to be a long day.". said Sunset pinching the bridge of her nose.