Fluttershy had to admit, the way her life proceeded from that conversation was something of a best case scenario. At the behest of Rainbow Dash she told her parents, who were shocked but accepting (Zephyr didn't seem to mind). They even went as far as to find a doctor in Canterlot who specialised in ponies like her. And she was glad they did, because meeting Doctor Stable led to what was possibly the best thing to happen in her life. After 4 or 5 visits, 8 months, and a lot of having the same conversations with a myriad of ponies, Doctor Stable prescribed her a specialised medicinal potion. Oh, Celestia bless that potion! One small sip every night, and little by little, Fluttershy's body would change. Not enough that you could see it happening, but as she grew to adulthood, her body would begin to match with how she felt.
However, things weren't perfect. Any bullying she experienced before coming out was increased tenfold, (sometimes, the chanting of "butterscotch, butterscotch, he's afraid of his own crotch!" would keep her up at night) and some members of her extended family stopped talking to her. She wasn't too fond of them anyway.
After many years, when people were finally able tell she was a mare from just a glance, Fluttershy moved down to the surface, in a cute little cottage at the edge of Ponyville, spending her days caring for any animals see came across. Truly, Fluttershy didn't think her life could get any better.
And then she met four very interesting mares, had an adventure in the Everfree forest, harnessed the element of kindness, and became part of group of lifelong friends. That was pretty great, too.
"Oh my gosh! I never realized how horrible it is not to be able to talk! I mean, I love talking so much and when I couldn't talk anymore, my tongue was all "EEEEEEEHHHH!". It was the worst! Don't you agree, Fluttershy?"
Fluttershy simply nodded. "yes." oh, it was good to have her voice back.
All the mares shared a laugh, happy to be free from the effects of the Poison Joke. All except Pinkie Pie, who was suddenly very interested in a random spot on the far wall. Soon, the laughter died down, and a comfortable silence settled between the six ponies. Fluttershy had been waiting for a moment like this. The yellow Pegasus swam up to Rainbow Dash and tapped her gently on the shoulder.
"What? Oh, right." Rainbow had been in enough of these moments that she know the meaning behind the look she got. The cyan speedster stood up in the large tub and cleared her throat. "Hey girls, Fluttershy has something to say!"
Twilight, Rarity and Pinkie all turned to face the Pegasi, Applejack made an effort to see the rest of the group from the bucket she was squeezed into, and any sounds that were being made ceased completely. Fluttershy suddenly became very interested in the bottom of the tub.
"Thank you, Rainbow. I want to tell all of you something important about myself. The reason... I really didn't like my voice... being like that- i-is because...i'm transgender.
"Sorry dear, what did you say?" Rarity enquired, "I couldn't quite hear you." Pinkie, However, had no such issue.
"Fluttershy says she's trans."
Preparing for a worst-case-scenario, the timid pony curled up into a ball and submerged herself, everything under her nostrils sinking below the waterline. The silence was broken by three sounds: a crack, a splash and a thump. In Fluttershy's mind, this was her fears being confirmed. In reality, Applejack had fallen out of her bucket. "She's what?"
"Transgender; " Pinkie began, doing her best impression of a university professor. "Adjective. Ponies whose gender identity are different from the sex they were categorized with at birth."
Applejack propped herself up to the tub, her front hooves hanging on the edge. "I ain't never heard'a those words. Pinkie, did you make that up?"
"Pfft, I wish. It's a whole thing, been going on forever." Pinkie turned to the yellow and pink ball curled up at the other side of the water. "Flutters, you have my full support. I'm gonna do some laps now!" The pink party horse sank to the bottom and began swimming back and forth.
Applejack was running out of patience. "And that means what, exactly? In normal words please?"
Ever the realization of elegance, Rarity attempted to clarify. "welI, it's a little complex, but I believe that Fluttershy is confessing to being, well... a stallion trapped in a mares body."
Fluttershy shot upright. "NO! I mean, it's the opposite. Or well, it was." She sank again. Rainbow Dash groaned. "It's actually pretty simple, everypony. Fluttershy was a colt, she didn't like it, She's a mare now. Are we gonna move on anytime soon?"
"Oh." Applejack took a moment. "Well... Okay then!"
The yellow pegasus raised her mouth above the water. "You're not... mad?"
"Mad? Fluttershy, what sorta pony do ya take me for? sure, we apple's might be an old fashioned bunch, but we're a varied one, and we stick together. Heck, I got gay ponies all up 'n down my family tree! Doesn't bother me none if you're a transgender!"
"It's not a noun!" Pinkie yelled, sinking almost as fast as she surfaced.
"Well, I personally feel honored that you trusted us enough to let us know, darling," Rarity cut in. "I must say I never would have guessed, I mean you truly look fantastic. Oh, but even so, you do get self-conscious very easily. Therefore, I must do something for you to keep you secure in your femininity!"
By this point Fluttershy had unfurled herself, and was tensely holding on to the tubs side. "O-oh no thank you Rarity. I don't want to be treated any different than before you knew."
"I HAVE IT!;" Rarity shouted, clearly in the zone. "Spa day! every mont- no, every week! The white unicorn slid her way to where the two Pegasi were seated. "Oh, just think about it, Fluttershy! A sauna treatment, hooficures, a massage, seaweed wraps, these wonderful mares at this magnificent salon will bring you to the absolute HEIGHT of womanhood!"
Hearing Rarity's animated description couldn't help but bring a smile to Fluttershy's face. "I think I'd like that."
Rainbow, formerly content to be a hoofs-off moderator of this discussion, had to bring something up. "Twilight, you've been pretty quiet." Saying this, She swam closer, forming an equine barrier between the unicorn and her fellow pegasus. "You don't have a... PROBLEM with this, do you?"
"No, of course not! You five are some of the best ponies i've ever met, and there's no way I would end our friendship over something like this! The problem is that I... don't understand." Dash lowered her stance. "that's it?"
Twilight looked away, frowning. "Rainbow, it's me. I'm not really comfortable with not getting things. I care about Fluttershy, but this just doesn't make sense to me. It may take me a while to come to terms with it all. I mean, I don't think I ever met a transgender pony before this."
Pinkie surfaced. "That's not true! You met Fluttershy!" Pinkie sank.
"Um, Twilight?" The pony of discussion speaking up was expected by no one, least of all the yellow Pegasus herself. "I think I might be able to explain how I feel, i-if you wanted." All eyes were on Fluttershy as she approached Twilight.
"You said that not understanding things made you uncomfortable, r-right?" Stunned by Fluttershy's determination to help her, to the point where she gave up her own rainbow security guard, Twilight could only nod quietly. "Well, I can get that way too, except it's a really bad kind of uncomfortable, the kind that just petrifies you. And I get uncomfortable at different things, like when... if somebody said I was a "f-fake Mare", or if I had to wear a suit instead of a dress, or..; She let her head fall forward. "...If I got exposed to poison joke, and it gave me a deep, male voice."
Twilight made the connection. "And that's why you wouldn't talk to us this morning!"
"Yes. You know Twilight, I don't know if I fully understand this myself. All I know, all I can tell you, is that being a Mare, it makes me happy. And, it's fine if it can't, do whatever's alright with you, but, can't that be enough?"
Twilight smiled warmly as she started to tear up. "For you, I'll make enough out of that."
At last, Fluttershy could release. The tension that struck and intensified within her from the second she confessed, so constricting that it felt like her body was being squeezed by a manticore, gone as if it were never there. Maybe coming here every week would be good for me.
Twilight was lost in thought for a moment then spoke again. "Say, Fluttershy, would you be okay with me ordering some books about this kind of thing? If I can find any, Of course. It's strange, I've read every book in the Library, and none of them- OH MY GOSH! Spike! he called you- Fluttershy, I am so, so sorry! I'll get him to apologize, don't worry!"
Fluttershy couldn't look Twilight in the eye. "No, that's okay. It hurts, but I can handle it."
Rainbow stood up. "But you shouldn't have too, 'shy! You deserve to be called what you are, and anyone who says otherwise deserves a smack 'round the head! When someone says something about you we all know is wrong, they have to be corrected. And if you can't do that, we'll do it for you."
"Totally right!"
"Darn tootin'!"
"Oh, absolutely!"
"Yeah!" Pinkie whooped, shooting to the surface like a reverse cannon ball. "The Elements of Harmony say Trans Rights!"