Zipporwhill's Strange and Convenient Butt

Weeks passed, and the fillies fell into a routine. Give Zipporwhill something to eat from the beach or the sea and some coconut milk in the morning, enjoy bountiful chocolate milk, chocolate mini-donuts, and lemonade in the afternoon. Eventually, even Scootaloo began to see Zipporwhill's rear as like a portable vending machine.
Out of laziness, the fillies would just come up to the relevant hole, then yank the tail as a signal for Zipporwhill to dispense. If they really wanted a good tasting, they'd stick their tongue inside. There wasn't much variety besides the occasional scent or taste of strawberries, but it was a welcome reprieve from the boring island or chatting with Apple Bloom about harvesting techniques.

Zipporwhill wasn't a big fan of this treatment, having slapped Scootaloo silly with her buttentacles when the orange filly started doing it, but after a while she relented to pressure from the three. Over time, they built some nice huts and a big fat rock arrow on the beach to signal to rescuers.

The fillies had almost given up hope of rescue after 2 months. Their coconut supply was nearly gone and, while there were plenty of fish for Zipporwhill's butt, none were sure how well they could survive solely on her excretions, especially without chocolate milk as an option.

Just as Sweetie was proposing trying a coconut-free week as an experiment, they heard the foghorn of a ship sound from sea.

"Rescue! We're saved from Sweetie's experiment!" Apple Bloom cheered and suddenly kissed Scootaloo on the lips, surprising the orange filly a bit with just a touch of spit swapping in the smooch before giving Sweetie and Zipporwhill the same.

Scootaloo spat a bit. "Blegh...just cause we're getting rescued doesn't mean ya gotta get all lovey-dovey on us! Let's go see the ship before ya get any worse."

The others shared a giggle before they all got going. Once past the palm trees, they could see it was definitely a rescue ship, and they could just about make out that there were blue, white, and orange mares on deck.

"It's them! We're goin' home everypony!" Apple Bloom cheered, and this time just hugged the 3 instead of smooching them.

Once the 4 were aboard, Nurse Redheart gave them some quick examinations. "Everypony looks quite healthy, no obvious signs of disease or injur-...Zipporwhill, what's that on your butt?"

"Oh, that. I'm not sure how to say this, but the meteor that separated us from the ship gave me uh, tentacles in my butt that I eat fish and other small creatures with."

Nurse Redheart practically dropped her magnifying glass. "WHAT? That...I..." She took a deep breath and assumed a calm voice again. "...please come to the infirmary with me alone, Zipporwhill."

The mane 6 had all gathered around and were staring at the brown filly's rear. Twilight seemed especially intrigued, and spoke up. "Fascinating...I wondered if the shockwave from that meteor would have any effect on a pony, but it happened too far offshore to affect anypony on land. This could open up whole new possibilities for magic!"

The other 5 remained speechless, leaving Sweetie Belle to try to explain further. "She also poops little chocolate donuts (or chocolate milk if she's got the runs), pees lemonade, farts strawberry gas, and sneezes taffy boogers. That's how we survived on the island. You gotta try some when Nurse Redheart's done, Rarity."

Rarity fainted so hard she nearly fell off the boat.