Sunset ran down to the dungeon and magically opened all the cell doors. She could tell which one was Princess Tiffany. Both her skin and hair were white and she wore a sparkling purple dress. She almost reminded her of Rarity.

"You're free," said Sunset. She quickly checked herself out and blushed when she realized she still wasn't clean, but Tiffany didn't seem to mind.

"Thank you," said Princess Tiffany. "What is your name?"

"I'm Sunset Shimmer, and I come from Earth. And Equestria. I'm really sorry you had to see me like this." She was covered in sweat, swamp water, fishy water, mud, pee, snot, and sewage, and her shorts were filled with poop. She smelled absolutely horrible.

"It's all right. As a matter of fact, as a reward for saving me, I can give you a bath in the sirens' bathtub."

"Are you sure you can put up with the smell?"

"I will. Where are the sirens now?"

"They fell out the window of their throne room."

"Guards, if they're still there, lock them in this cell until I return."

"Yes, Princess!" said the guards, and they ran out of the room.

Tiffany took Sunset to the sirens' bathroom. It was a fancy-looking bathroom with a big bathtub, which had a shower in it, and Tiffany found all kinds of soap and shampoo in the cupboards.

"Hold on," said Sunset. "I may have soiled myself pretty bad, which could make washing me awkward. I'll be right back." Sunset ran out the door, and returned about five minutes later. "My mess is now on Adagio's bed."

Tiffany laughed. "Well, I don't think she'll be using it again anyway. Are you ready for your bath now?"

"Yes."

"First let's rinse you off in the shower."

Sunset stepped into the bathtub, not removing her filthy outfit as it needed to be washed as badly as she did. Tiffany turned on the shower, and Sunset stood under it, greatly enjoying the warm water as it rinsed much of the gunk and slime off her. When Tiffany turned off the shower, Sunset was still dirty and smelly, but considerably cleaner.

Then Tiffany put the plug in the drain and turned on the water. Sunset sat down as the tub slowly filled with water, and Tiffany put soap in there to make it a bubble bath. Once the tub was full, Tiffany lathered Sunset's hair with shampoo. Sunset really appreciated this. Once Tiffany was done, she put some soap on a scrubber and scrubbed Sunset's back, covering her in suds.

"Thank you for doing this," said Sunset. "I wasn't looking forward to returning to camp like that."

"Thank YOU for rescuing me," said Tiffany. "It really wasn't pleasant being locked in that dungeon for a week, and I'll need a shower when this is done too."

Bubbles suddenly appeared around Sunset in the tub. Sunset blushed. "I'm so sorry, Princess. I didn't mean to."

Tiffany just giggled. "I don't mind. I actually find it kind of funny. Besides, it's not as unladylike as me peeing through my underwear in the corner because there were no toilets in the dungeon and I really don't want to expose my nether regions. They gave me Kan'u Juice too so I had to pee like every hour."

"Oh. I'm sorry to hear that. Are you all right?"

"I suppose it's better than what you had to go through, and I'm over it already." Tiffany started to scrub Sunset's sides and smelly armpits. "But when I had to go to the bathroom in the OTHER way, I did pull down my panties, and kept everything hidden under my dress."

"Well I'm glad you didn't mess yourself," said Sunset. "It's REALLY unpleasant."

Soon Sunset's entire top half was covered in suds. Tiffany tentatively said "Um... is it all right if I..."

Sunset got on all fours so her butt was in the air. "If you don't mind. My shorts smell even worse from using them as a toilet so much."

"If you don't mind, neither do I." Tiffany scrubbed Sunset's butt really hard, creating more suds than was on her top half. Sunset enjoyed this. She hoped she wouldn't accidentally fart in Tiffany's face, but she didn't. Once Sunset's stinky shorts were covered in suds, Tiffany scrubbed her legs. "All right, you can sit down now." Sunset resumed sitting position, and Tiffany raised her lower legs and washed them. When she started to scrub her feet, this tickled Sunset, who splashed around in the sub, soaking Tiffany.

"Sorry, Princess," said Sunset when her feet had been washed and she stopped splashing.

"It's all right," said Tiffany. "I really need to wash too." She sniffed her armpit and recoiled. Sunset hadn't noticed Tiffany's smell over her own.

Then Tiffany poured warm water over Sunset's head to rinse the shampoo out of her hair. She drained the tub and rinsed Sunset under the shower one more time.

Sunset stepped out of the shower, dripping wet and with no visible signs of how dirty she had been earlier. "How do I look?"

"Clean," said Tiffany.

"And how do I smell?"

Tiffany sniffed Sunset and recoiled. "You... might want to wash hard every day if you want to get the smell out."

Sunset sniffed herself and sighed in disappointment. "Well, it's better than before, at least."

"Now, let me take a shower." Tiffany stepped into the shower and washed herself off. Like Sunset, she didn't undress, her dress was already wet from Sunset splashing her and smelly from not washing for a week. She exited the shower. "How do I smell?"

Sunset sniffed her. "Clean," she said.

Tiffany walked into another room with Sunset. Inside was a gem similar to the geode. She picked it up and absorbed its power and grew pegasus wings. "It'll take a lot faster to fly back to the kingdom than to walk there. I'll give you a ride."

"Are you sure? It's a long way."

"I'm stronger and faster than I look. Besides, you're the reason I'm not rotting in a dungeon peeing my panties anymore, and you went through a lot to get here."

"Then, thank you so much. Can you drop me off at the cave near the land of giant food? That's where the portal to Earth is."

"Sure."

"What about the guards?"

"Some of them have wings when they get their power back. They'll carry those without wings, and the sirens."

Once they were ready, they took off, Tiffany carrying Sunset, and three of the guards carrying the smelly sirens.

As they were flying above the desert, Sunset said "I have to pee." It had been an hour since the last time and there were still four days before the effects of the juice would end.

"I could set you down and tell everyone to look away," said Tiffany.

"No thanks, I'll hold it."

It took a few hours rather than days but they reached the edge of the desert at the land of giant food.

"There's the bathroom," said Tiffany, pointing to it.

"Actually... I don't have to go anymore." Sunset blushed.

"Oh. I'm so sorry."

"It's all right. The desert heat dried me, and I already smell."

"Well, thank you again for saving me, and you're always welcome to return."

"I'll be sure to bring my friends here sometime. Goodbye."

"Bye."

Sunset walked through the cave and through the portal back to camp. She sniffed herself to see if returning to her world would make the smell go away. It didn't. She sheepishly walked over to the other girls. "I'm back."

As soon as her friends got near her, they caught a whiff of her.

"Phew, you smell just awful," said Applejack.

"Yeah, I know," said Sunset.

"Did you get sprayed by a skunk?" Pinkie asked.

"It's kind of a long story."

"You've only been gone a minute," said Twilight.

"A minute? I was there for almost a week."

"Ooh, I remember reading something about the possibility of other worlds that run on a different time than here." Twilight was really excited about this.

"So, if you can put up with my smell, I'll wash hard every day and hopefully get it out soon."

"You smell rather foul, but we can put up with it and give you a major wash every day," said Rarity.

"Thank you," said Sunset.

"So, are you gonna tell us what happened?" Pinkie Pie asked, sounding interested.

"Well, I was on my way back from the outhouse when I saw a light inside a cave, and..."

Sunset told her story, and allowed Rainbow and Pinkie to laugh when she mentioned wetting and messing herself, or wedgies. Afterwards, they continued to have fun on their camping trip, despite Sunset's stench.

They were at camp for another two days. Sunset still needed to pee a lot, but made it to the outhouse every time, except first thing in the morning. But she wasn't too ashamed of it, plus Pinkie told her from personal experience that the pee smell comes out easy.

Once they got home, driving with the windows open, they washed her in a wooden tub, still in her smelly outfit, scrubbing her with lots of soap. They washed her for an hour yet still couldn't get the smell out, though it did decrease slightly. That night she put her wet, smelly outfit in the wash as she changed into her pajamas, but it only decreased the smell as slightly as washing her had. So she decided to stay in this outfit the entire time while they continued to wash her every day. After about a week, both she and her outfit were finally clean of the smell and she was able to put the whole experience behind her.

And as for the sirens, Princess Tiffany had them put in the stockade for a week, in which they were fed the same drink and fruit as Sunset, as well as another fruit that would give you explosive diarrhea for a few days. Though they were still covered from head to foot in horse manure (which somehow hadn't dried in the desert heat), this didn't make soiling themselves repeatedly any less unpleasant. The horses, elephants, and monsters would also walk by and pee on them often. Once the week was over, they were locked in the dungeon. There was a toilet in the dungeon, as their week of torture was over, but they were so filthy at this point they just went in their pants.

After a month, Sonata gave a sincere apology and was released, starting a new life after a major wash, but Adagio and Aria were too stubborn and remained in the dungeon in their messy state to the end of their days.

Author's Notes:

Credit to clipclopurpornisaflop for giving me the idea of Tiffany washing Sunset before her return. My original draft had her return to camp before getting a bath from her friends, but I liked this better. Also, the sirens' defeat went through a few phases, I wanted a balance of something not too stretchy and comeuppance for what they did to Sunset.