Sunset Shimmer was feeling sad. When the portal to Equestria closed for the last time, she had thought it did so with the promise of her friends’ eventual return.
For a while she went about her life as usual, but steadily her thoughts began to turn to the world on the other side.
The thought of never seeing her old home again began to loom in her mind, and after every school day she would glance at the statue where Twilight had first emerged, the stillness sending a twinge of pain through her chest.
In time she started to question if any of it was real; the monotony of everyday life wearing away at her fantastic memories, her subconscious revising them.
It is for this reason that, one otherwise ordinary day, when she came across a crack in the statue emitting an ominous green light she felt no apprehension upon diving right in, fearful that it too may be erased if she were to hesitate.
As she swam in the alien light, a flutter of hope welled within her, like her sleepy heart had hit a speed-bump.
Within that crevice Sunset saw something that no one was ever meant to see. Glowing strings stretched across a vast expanse, binding together multifaceted shapes of impossible dimension that shimmered with internal light.
Some were sky blue, others filled with stars; she even caught a glimpse of a familiar sunset, reminiscent of the view from the ramparts in Canterlot, the last sight she had seen before her banishment.
This particular prism was unusual in that there was no glowing string. Instead, a dull and sickly rope dangled flaccidly into space.
She thought that if she could reach it she could pull herself in, yet as she swam forward she was caught in a sudden current, sending her tumbling off course and into another unanchored shape drifting by.
She spilled into that world from a mirror, tumbling into an unfamiliar bedroom.
An unfamiliar pegasus attempting to use the mirror to take a selfie stared down at her with curiosity. Sunset made note of her unusual headband, then noticed two others in the room: a unicorn with a tennis ball on her horn and an earth pony with a satchel slung over her shoulder.
The sudden flash of a cellphone camera caught her off guard, and she realized that she was sprawled out on her bum with her legs tented, the flare of her skirt open like a flower to show off her stark white panties.
“H-hey! Did you just take a picture?” she said in disbelief, stumbling to her… feet. She marveled briefly at the fact she had not been transformed. In the meantime, the other two ponies had taken notice and soon had her cornered in front of the mirror.
“Whoa, what are you?” asked the earth pony, adjusting her satchel.
“She’s a human, duh.” Said the pegasus without looking up from her phone.
“Are you alright?” asked the unicorn, looking at her innocently.
Sunset looked down at her boots, then at the shimmering horseshoes of the others. She was still human, but why?
The unicorn glanced over at her friend’s phone. “Pipp! You aren’t going to post that, are you?” she squeaked.
“Post what?” asked Sunset, suddenly nervous. “You mean that picture you took?
“Yep.” said Pipp, and Sunset felt her muscles tense.
“Could you maybe, I dunno, not do that?” she asked with annoyance. The pegasus merely blew her mane out of her face and ignored her.
Having run out of patience, Sunset made a clumsy attempt to swipe the phone, which Pipp sidestepped, holding out her hoof for Sunset to trip over.
When the unicorn stepped in to try and catch her, their lips met in an unplanned kiss, the pony girl’s look of surprise melting into one of contentment as Sunset dug her hands into the fluffy coat of her chest in an awkward attempt to arrest her fall.
Pipp snapped another a photo while the earth-pony stared in disbelief.
The unicorn, whose name Sunset would later learn was Izzy, stiffened her wings, her eyes fluttering open a moment before her own.
Blushing, Sunset pulled away, her mind in a fog. She felt like she should say something, but all that came out was: “Why do you have a tennis ball on your horn?”
Izzy blinked, then tried to look upwards before realizing what Sunset was talking about. “Oh, that.” she said with a giggle. “So I don’t poke anypony’s eye out.” She winked, and something stirred within Sunset’s chest.
“Is that really why?” asked Pipp, looking up from her phone, suddenly interested.
Sunny, the earth pony, stamped her hoof. “Don’t you remember?” She asked, then began to look around, as if seeing the room for the first time. “Wait a minute. Something isn’t right.”
Izzy followed Sunny’s gaze, a look of concern forming in her delicate features. “Come to think of it, I don’t remember how we got here.” she said at last.
Even Pipp briefly lifted her head to glance at the empty and windowless walls.
Sunset looked back at the mirror, seeing only her own reflection. Did she really emerge from there?
A familiar feeling of doubt began to settle over her like a wet blanket, and she stiffened against it.
“I remember how I got here.” she blurted. The ponies looked confused, with the exception of Pipp.
“How? I didn’t even see you come in.” said Sunny.
“I did.” replied Pipp. “She came through the mirror.”
The others looked to Sunset for confirmation. “That’s right. I think I can lead you out the same way, but we don’t have much time. You’ll just have to trust me.” She looked at the unicorn when she said this.
Izzy blushed, then stepped forward. “I trust you.” she said, smiling, placing her hoof over her heart. There were no objections from the others, and so the four of them slipped through the looking glass and into the in-between.
Author's Note
Well, this is a thing that I wrote that might be somewhat confusing, but will hopefully serve a purpose for the modest realm(s) of my semi-erotic fiction. It isn’t a particularly serious piece, nor is it overly erotic, but hopefully has some substance to it. 
I was inspired by the notion of Equestria Girls continuing into Gen 5. I wanted to capture the sentiment of concern over the future, depicted as a crushing feeling of decline while expressing another feeling: that of being left behind.
I thought this was also reflected in the apparent state of the world depicted in the adverts for the New Generation, where it seems that magic (which is tragic, if friendship is magic
) has been all but forgotten.
There seems to be some debate over how Gen 5 relates to FiM. Personally, I enjoy the speculation, but am not too concerned about the specifics. Fiction is fiction, after all, and whatever comes next doesn’t necessarily take away from what came before. Nevertheless, this seemed like a fun opportunity to explore the possibility of multiple, disjointed realities while creating a convenient precedent in case I want to cross over some of my own stories set in different universes someday.
Also, I thought Izzy was cute, and wanted to do something with her. 
