An hourglass isn't your Cutie Mark

by Rupertthered

First published

When Twilight tries to learn a new spell, Pinkie and Rainbow Dash mess it up.

Contains Hourglass expansion, which means Breast Expansion and Butt expansion, no sex, but has groping, and facesitting. This is my 2nd request, that will have three chapters.

Characters are Anthro.

When Twilight discovers a spell that can shrink and expand items, she decides to run a few tests first using potions. As she goes to grab an ingredient, Pinkie and Rainbow Dash decide to play a prank, that backfires at them.

The beginning

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It was a normal day in Anthroville. Nothing horrible has happened for a long time. It seemed great, finally some peace and quiet. That’s exactly what Twilight wanted this whole time and now she would get it. In her library she had set up her chemistry set working on new experiments. She had sent Spike away to do whatever he wanted as she concentrated on about her business.

Recently she had learned about a quick storage spell. It would allow a unicorn the ability to shrink items to store them rather quickly. As well as expand them, so the object can return to normal. This seemed like a great idea to her. With such a spell, she can quickly relocate any item she needed whenever she wanted to. Well if she remembered where she left it though.

She began to mix different components for the potion. She didn’t want to learn the spell yet; she wanted to try a live demonstration before finally deciding on what to do. She decided to make an expand potion first incase she spelled the shrink potion on herself, she had a way to restore herself. At least if she enlarged herself, she can try to fix it and not worry about being squashed. The potion was almost done; she just needed to grab the final ingredient in her basement. This was probably a bad idea for her, but not for the two pranksters that were sneaking in.

One slender figure opened the door followed by a somewhat chunkier figure. The smaller one talked, “You sure this is a good idea?” Doubt in her voice, but there was still excitement.

The other spoke. “Oh, don’t worry Dashie, when do my plans ever fail?” She walked past “Dashie” as she examined the chemistry set.

“Dashie” sighs upon hearing her nickname. “Most of the time your plans do fail Pinkie, but I suppose I’ll trust you for this one. And can you try to stop calling me Dashie, you know I don’t like that nickname.”

“But you know I like calling you that. I have to give everyone a nickname.” Pinkie replied. “But fine Rainbow, I won’t use it.”

“Thank you Pinkie. Now let’s do this before egghead returns alright.” Rainbow complained, pointing at Twilight’s table.

Pinkie giggled. “Don’t worry Rainbow, everything will be just fine, watch this.” She began to step over to the table where Twilight has everything set up. “Now all we need to do is grab this.” Pinkie reached into her hair to pull out what appeared to be salt and pepper. She giggled yet again as she began to sprinkle them into what seemed to be the main vial. Though Pinkie never thought about the effect the pepper would have on her in such close range. Pepper began to feel her nostrils, and she can feel a sneeze coming through. “Umm Dashie, I think I made a mistake.”

Rainbow annoyed hearing her nickname again. “Yea you used that nickname instead of saying my name.” Pinkie was still trying hold back the sneeze. “It’s not that I think the pepper is getting to my nose and I’m about to sneeze.” Rainbow’s eyes grew wide. “You gotta be kidding me.” Rainbow tried flying over to stop Pinkie from sneezing which did work, but the pepper now went into Rainbow’s nose, as she forcefully sneezed outloud.

The sneeze being quite forceful the potion Twilight was working on splashed everywhere. “Oops, I hope that doesn’t do anything to us strange.”

Rainbow spoke up rather loudly. “Oh no, of course not Pinkie, it’s not like an experiment with untold possibilities can do anything bad ever.” Just then a stretching noise can be heard. “Umm Pinkie what are you doing?”

Pinkie looked around also hearing the noise for the first time. “It’s not me.” The noise was truly distracting till they heard the door open over to the side, and there appeared their purple anthro unicorn friend.

Upon opening the door with the final ingredient in her hand, she found her work spot in a disaster. “What happened here?” If Twilight was mad enough at Pinkie back during her Pinkie senses time, then she was furious at seeing this. Soon enough though Twilight too heard the stretching noise somewhere close by. “Oh, when I find you, you better wish I can somehow research this or else I’ll, I’ll do something very bad.”

Twilight eventually found herself in the kitchen where she saw two figures muttering to each other behind the table. “Aha, found you. Now what’s going on?” She looked at the two figures and recognized the two almost immediately. The rainbow mane and cyan winged anthro mare tagging along with a pink haired anthro mare. “Rainbow? Pinkie? What did you two do?”

Neither wanted to speak as they knew the source of the stretching noise was, Twilight was impatient and pulled them both up to their feet. Before her eyes, she can see rips and tears in their clothes. Her eyes open wide as she witnessed her potions affect her friends. She didn’t think it would have an effect like this.

Rainbow Dash never had boobs to speak of, but soon her top was going to rip trying to contain their evergrowing mass. Her ass, always shapely and toned, also gained mass, though it seemed to be growing faster than her breasts were. Pinkie seemed to have shared the same effect. Her “fun bags” as she called them were moderately gaining more volume threatening to ruin her shirt. As well as her bubble butt was expanding faster just like Rainbow’s was. Eventually the clothing of the two finally ripped in half, save for their panties and bras which were still holding on barely.

The stretching sound stopped, the three mares stood there in silence, till Rainbow spoke up. “Umm Twilight what kind of potion were you working on there? A sex me up potion?” Anger in her voice.

Twilight couldn’t help but face palm at what Dash had just said. “It was a simple expand and shrink experiment I was working on. I didn’t want to learn the spell yet, as I wanted to run some tests first. It’s suppose to enlarge and shrink objects but apparently you two did something that causes certain parts to grow instead. This was suppose to make traveling easier.”
Off to the side Pinkie had decided to start poking at her new assessments always feeling a tingle here and there, and letting out “Oooo”s and “aaah” at times. “This is really a neat-o spell Twilight. Were you trying to impress some colt? It’s okay if you’re insecure about your looks Twilight.”

“What?! No, it’s not that, I was trying to learn a new spell that would make transportation easier, but you two messed it up.” Twilight defended herself, but Rainbow didn’t seem to buy it. “Anyways, now I have to run tests on both of you, to see what kind of effects it has on people. I’m hoping it’s nothing bad.”

“You can’t be serious Twi, I’m suppose to practice my flying later today.” Rainbow pleads. Pinkie though didn’t seem to care.

“Well I doubt you’ll be doing much flying due to your new assets.” Twilight points at Dash. “Besides, that’s what you two get when you go messing around with things you shouldn’t be touching.” Twilight decided to bring them both to her living room, as she entered using her magic she decided to move everything as to not damage anything else. “Alright, well since it seems the potion has expanded certain features of the female body, I need you two to start playing with each other, but no sex. I don’t know if there is some kind of side effect when sex is involved.”

Dash rolled her eyes. “So what are we suppose to do then?”

Suddenly Pinkie’s face was in front of Rainbow’s. “This silly.” Soon enough Pinkie’s hands fell upon Dash’s expanded exposed breasts. “See doesn’t it feel nice?” Rainbow had to admit it did, she was always a flat chest, and with this new potion she can see what it was like, she moaned quietly, as Pinkie touched here and there. “Oh I know, my turn now.” But instead of leaving the front of her body in front of Dash, she turned around and made her booty rise up.

“Umm Pinkie what are you doing?” Soon Pinkie’s butt came down on Dash’s head like that one time when Pinkie was crazy. Rainbow’s head hitting the floor, her stomach on the floor, with Pinkie’s ass on her.

“Oh yea, that felt great, butt it didn’t feel good enough.” Pinkie giggled to herself as she made the joke. In the corner Twilight kept watching observing, taking notes on what her friends did.

“Hmm, the potion doesn’t seem to have done much but made their assets bigger and possibly more sensitive.”

“Ha you said ASSets.” Pinkie laughed as Twilight’s face grew red from what Pinkie pointed out. “Having fun Dashie? I know I am.” Pinkie’s bottom jiggled a bit as she shifted a bit back and forth.

Rainbow Dash wasn’t assumed by this and with all her strength tried to get up, but to no anvil she couldn’t lift Pinkie’s and her expanded butt, due to Pinkie’s size, and Dash’s new chest. “Alright Pinkie fine I get it, it’s big.”

Twilight still wasn’t sure how to react to this development at all, but soon she found one, as she saw her friend’s assets began to glow, and soon their boobs and bottoms began to shrink back down. “Woah, its only temporary huh?” Twilight began to write it down, not paying anymore attention to the two.

Rainbow finally not pressed down by such a heavy weight lifted up. “Pinkie what were you trying to do? Suffocate me? That wasn’t funny.” Pinkie simply laughed.

“I certainly had fun Dashie, I’m sure you did too.” Pinkie winks at Dash, who suddenly starts looking around the room. “Come on silly, let’s go, Twilight has some serious stuff to take care of.” With that Pinkie dragged Rainbow out of Twilight’s house.

Twilight now all alone, had an idea how to spend the weekend, but first she needed two more test subjects to try out some stuff.