"Ugh, come on, Rares. How much longer could you possibly need?" Rainbow Dash whined.
"Rainbow Dash, please, just hold still a bit longer. The Wonderbolts Ball is a formal event, and you need to be in your formal dress uniform... a uniform, may I add, that you decided to wait until the last moment to purchase," Rarity said, humming as she pinned her friends' overly-long cuffs in place.
Rainbow Dash stood stock-still, fidgeting occasionally, as Rarity worked around her. Measuring tape, needles, thread, and pins floated in Rarity's telekinetic grasp. Rainbow, for her part, wore her formal Wonderbolts uniform, which consisted of a navy-blue jacket over a white collared shirt. Her jacket, unfortunately, had hung a bit long on the petite pegasus, and she was left looking like a child that was wearing her parents' clothes. Rarity had fixed that quickly, with some careful measurements and pinning, and it was looking far better. All that was left was to complete the alterations and bring it in at the sides to show off Rainbow's svelte, athletic frame. Rarity stepped around her friend, taking in the outfit from all angles, trying to spot any other places that needed some adjustment. She also gave herself a brief, selfish moment to appreciate her friend's toned form. She was moderately jealous of her friend, if she was being honest, but she knew that Rainbow Dash worked for her figure. Rainbow Dash glanced over her shoulder at Rarity. "Are we almost done?"
"Yes, darling. Hold still and I'll take it off of you," Rarity said, her horn lighting up. Rainbow Dash stood still as Rarity's telekinesis unbuttoned the jacket and carefully slid it off of her, moving only enough to allow Rarity to pull the jacket off. The white collared shirt came next, and finally Rainbow Dash was given the chance to stretch her wings and legs properly. She shook herself like a dog, sighing. Rarity giggled. "That wasn't so bad, now, was it? Do stick around, darling, the sewing will only take me a short while."
Rainbow Dash shrugged. "Sure. I don't really have anything better to do until the ball." She stepped off of the raised platform she'd been on for the better part of a half-hour and followed Rarity into her work room. The work room was a bit of a mess, with fabric and patterns scattered about with the tools of her trade in and among the creative detritus. Rainbow whistled, looking around. "Wow, Rarity. If I didn't know any better, I'd say that we'd gone into my room."
"Mm, well, creative pursuits require a bit of... mess, on occasion," Rarity said, shifting a few bolts of cloth off a cushion for Rainbow Dash to sit on. "Besides, there's far too much lace and ruffles here for it to be your room."
Rainbow Dash chuckled. "True enough." She plopped down on the pillow as Rarity brought her uniform jacket up to her sewing machine to complete the hems and other work. Rainbow watched carefully, her eyes sliding from the sewing machine to Rarity, herself. Her friend was focused, her brow furrowed in concentration, her mouth set in a firm line. Rainbow Dash watched her work, quietly impressed by her focus and dedication. Rarity was pretty incredible, if she was being honest. A really... put-together mare. Rainbow Dash found her eyes following the curl of her friends' mane, almost hypnotized by the tight curl and light flounce of her hair.
Rarity noticed Rainbow watching her and smiled gently at her friend. "Taking an interest in sewing, darling?"
Rainbow glanced away. "N-no. I'm just bored."
Rarity giggled. "Certainly. Well, if you want to stretch your wings, that's fine, but first, tell me about this soiree you are about to attend."
"Oh. The Ball. Yeah, it's... cool, I guess," Rainbow Dash said, sitting back and stretching. "There's gonna be a bunch of supporters and bigwigs there, along with a lot of the Wonderbolt Alumni. We're all supposed to do a lot of hoof-shaking and stuff. I think it's gonna be boring, but Spitfire told me that they had some of the best catering in Canterlot providing the spread..."
Rarity paused in her work, looking at Rainbow Dash with a raised brow. "You're attending the ball for the food?"
Rainbow Dash grinned. "Heck yeah!"
Rarity rolled her eyes and focused once more on her work. "Honestly, high society functions are wasted on you. Imagine all the inroads you could make if you went there with the right mindset!"
Rainbow Dash shrugged. "Eh. I'm no good at that kind of stuff. I'll go and smile for some photos and shake a few hooves, and then eat ten plates of all the good stuff and take a nap."
Rarity snorted, and moved to the next hem she needed to adjust. "Well, I certainly hope that the food is good, darling."
"Yeah. I just..." Rainbow Dash stopped, staring at Rarity. "... I think it'd be more fun if I had a friend that could go with me."
"Mm, yes, that'd be nice, wouldn't it?" Rarity hummed, but noticed Rainbow's gaze and turned her attention to her. "... what? Is there something on my muzzle?"
Rainbow grinned. "... Do you want to be my plus one?"
Rarity froze up, blinking at Rainbow Dash. "Y-you can bring a plus one?!"
"Yeah. I totally forgot about it until just now, but I bet you'd have a blast, and you could keep me from making a bunch of fake paws," Rainbow Dash said.
Rarity managed to stammer, "It's faux pas, darling... but, are you certain? It wouldn't be an imposition on my part?"
Rainbow waved a hoof in the air, "Nah, no way."
Rarity giggled happily and grabbed Rainbow Dash into a tight hug. "Oh, thank you, Rainbow Dash!" Rainbow gasped as she was squeezed in Rarity's arms, her muzzle buried in the top of her mane by virtue of proximity. Rarity smelled like vanilla and roses, some kind of floral shampoo, and it tickled Rainbow Dash's nose and left her blushing profusely. Rarity released Rainbow Dash after a moment and turned her attention to the jacket. "I must finish these alterations, first, and then I'll have to get ready and—oh, goodness, what should I wear! You're going to look so nice in your dress blues! I'll have to create an ensemble to match!"
Rainbow rubbed the back of her neck, feeling a little spike of anxiety. "Oh, yeah. I guess you gotta wear something formal, too, huh?"
"But of course, darling! I could hardly expect to show up in the nude!"
Rainbow Dash rolled her eyes. "Rares, we're always nude."
"It's the principle of the thing!"
Within a few minutes, Rarity had completed the work on Rainbow's jacket, and she insisted that she put the whole uniform on once more. Rainbow grumbled as she worked her way back into the white collared shirt and jacket, and Rarity pulled a full-length mirror out for Rainbow to take a look. Her complaints caught in her throat as she saw herself. The jacket was like a new piece of clothing. Rarity had pulled it in at her barrel and set the shoulders and hem lines just-so, to show off Rainbow's curves and figure. It clung in just the right places, and was comfortable in others, and it made Rainbow Dash feel... "Woah."
"Yes?" Rarity prompted.
"Rarity, it's..." Rainbow turned in place, checking herself out from another angle.
"Yes?" She leaned forward.
"It's..." Rainbow turned in a slow circle, fluttering her wings and swishing her tail.
"Say it, darling~!" Rarity sang.
"Awesome!" Rainbow declared, jumping in place and striking a pose, popping one hip out with a little feminine strut. "I feel great!"
"Excellent! Then, my work here is done... or, perhaps, it is just beginning! Now I have to pick something that's equally, ah, awesome, as t'were!" Rarity said, hopping up from her seat and heading for the stairs up to her room above the Boutique. "Come along, darling, and help me pick out something nice to wear!"
Rainbow Dash grinned and followed Rarity upstairs and into her bedroom. Rarity gestured to the edge of her bed, a large four-post affair. "Sit there. We can make a bit of a show out of it!"
Rainbow Dash sat at the edge of Rarity's bed and grinned as Rarity disappeared into her closet. Within a minute, she strutted out, wearing a bright red, clingy, high-cut dress that made Rainbow Dash's jaw drop. "Holy crap, Rares," she said, blushing. Rarity looked hot.
Rarity grinned, waggling her eyebrows at Rainbow Dash as she turned a circle, her tail flicking tantalizingly. "Hmm, well, I'm glad you appreciate the cut, darling, but perhaps it's a bit too much. Something more... subtle?"
"Y-yeah, more subtle is good," Rainbow Dash said, managing to recover some of her cool. Rarity trotted back into her closet, and returned to the room a few minutes later wearing a black, shimmery dress with dazzling sequins. Her every move and sway of her hips sent sparkling waves across the fabric of the dress. Rainbow had to physically grab onto the bed spread to prevent herself from falling off. "Woah."
"Sparkly, isn't it?" Rarity asked, eyeing Rainbow Dash and sidling up next to her. She frowned once she got close, holding up the hem of the dress and comparing it to the color of Rainbow's jacket. "Hmm, no, this particular shade of black clashes horribly with your navy jacket. Let's try something different."
"B-but... I like that one," Rainbow Dash feebly protested as Rarity once more slipped into her closet. When she exited once more, she was wearing a cream dress cut to a more conservative length with a black sash. This dress flowed like water across her form, rippling with her movements in an ethereal manner and clinging in all the right places. It left Rainbow speechless.
Rarity sashayed up to Rainbow Dash and reached up with one hoof, closing Rainbow Dash's open mouth. "Mm, yes. I do believe that this is the one."
"Yeah. Me like," Rainbow Dash said, nodding rapidly.
"I can tell," Rarity said, giggling as she brushed a hoof across Rainbow's burning cheeks. Rainbow squirmed in her seat as Rarity turned and walked to her vanity and began to apply a fresh layer of makeup.
"T-that looks really nice on you, Rarity," Rainbow finally managed to squeak out. "You know... you don't have to do yourself up on my account."
"Nonsense, darling," Rarity chided, clicking her tongue. "It wouldn't do to have one of the most dashing Wonderbolts show up with a plus one that looked anything less than equally marvelous."
Rainbow Dash blushed. "Yeah, well, any one of the Wonderbolts would be lucky to have you, even if you were wearing nothing at all."
Rarity glanced over her shoulder and shot Rainbow Dash a saucy wink. "I'm sure a few of them would wish for 'nothing at all' if they were in your position, hmm?"
Rainbow Dash chuckled. "Yeah, I guess they probably won't all be so lucky to have such hot dates with them."
"Hmm," Rarity hummed, smirking at Rainbow Dash. "So, it's a date, now, is it?"
Rainbow Dash froze in place, feeling sweat start to build on her forehead. "Uh..." She mentally shrugged, and put on her most daring grin. "Yeah. Heck, why not? Sounds fun, right? Way less boring than being a 'plus one', right?"
Rarity laughed, "It does at that!" She finished applying her makeup, and added a spritz of perfume as a finishing touch. A floral bouquet tickled Rainbow Dash's nose as Rarity stepped close. "You do look dashing, you know. I think any mare would be lucky to have you as their date."
"Y-you're... not just any mare, though, Rarity," Rainbow Dash said gently, her ears folding back.
It was Rarity's turn to blush. She reached up and straightened Rainbow Dash's tie, and nodded. "Well then, darling. Shall we go?"
"Yeah. A chariot should be at my house in a few minutes," Rainbow Dash said, extending one hoof and offering it to Rarity.
Rarity smiled and took her hoof, and they walked out of the Boutique together.