"So, do you have a nickname?"
The question came out of the blue during a routine training exercise. Captain Spitfire glanced over at her flying partner, Rainbow Dash, who leveled her with an inquisitive stare.
Spitfire blinked a few times. "What do you mean, Dash?"
Rainbow shrugged. "I mean, I remember you guys telling me that each Wonderbolt has their own embarrassing nickname. Like with you guys sticking me with 'Rainbow Crash'?"
Spitfire lowered her ears. "We're sorry again about that whole mess. We never meant to make you feel unwelcome in the group."
"Water under the bridge." Rainbow waved a hoof dismissively. "But we're getting off-topic. What's your nickname, Cap? I figure I should know, seeing as how you're gonna be seeing more of me."
Spitfire smirked. "Dash, Spitfire is my nickname."
Rainbow's jaw fell open as her eyes slowly bulged from their sockets. "Wait…I-what?!"
"You didn't really think that was my actual name, did you?"
"B-But, I mean-how?!" Rainbow stared incredulously. She then leaned in with anticipation. "Tell me everything! No details left out!"
Spitfire rolled her eyes. "Alright, alright. Guess you earned it with the amount of training you breezed through today."
Rainbow nearly achieved Pinkie Pie-levels of giddiness as she bounced on the clouds.
"So, it went a little something like this…"

Inside the mares' locker room of Wonderbolt Academy, the pegasus who would become Spitfire thrashed on the ground as sweat beaded on her forehead. She was zipped up and trapped inside of her blue Wonderbolt-themed sleeping bag, with a large padlock keeping the zipper stuck together. A large strip of tape was pressed over her muzzle to prevent her from yelling for help or belting out any curses. The fiery pegasus bounced up and down like a wily tatzlwurm, grunting and moaning behind her gag as she struggled to escape her fleece prison. Her wings and limbs were pinned to her sides as she wriggled around on the textile floors. As Spitfire panted through her nose for breath, she leaned over to see one of her fellow recruits eyeing her mischievously. The blonde-maned pegasus called Surprise leaned against the doorway as she smirked at her helpless flying mate.
"Dang, girl, that's gotta be about thirty minutes." Surprise let out an impressed whistle. "And you still got a ton of stamina in you."
"Bhhk ymmh!!" Spitfire seethed.
"Whoa, now, don't pop a blood vessel! You're almost halfway through your initiation."
"Bhhk yrr initihhnn! Ghh mmh ouh of hrr!!"
Surprise chuckled as she stepped over to Spitfire. "You know what? I think you earned a little break." She leaned down and peeled off the tape from Spitfire's muzzle.
"Gah! I'm sweating like crazy in here! When am I gonna be through with this stupid, Tartarus-damned initiation?!?!"
"Jeez, you could stand to watch your language."
"You ain't my CO, so I'll say as much bucking language as I want!!"
Surprise scoffed. "Look, you only have thirty more minutes to go. No biggie."
"Look, just go tell the others I changed my mind. Taking over their janitor shifts is looking a lot better than this 'resilience test', or whatever it's called."
"They're all probably busy watching that magic show in the auditorium," Surpsie explained.
"What?" Spitfire balked. "But I thought you said they were right outside keeping track of time."
Surprise's brows shot up. "Oh, uh-yyeah! Yeah, that's what I meant to say! They, uh, weren't interested in going 'cause they wanted to see you through initiation!"
Spitfire slowly arched a brow at her flying mate. "That's the biggest load of horseapples I've ever heard. And you were never that good a liar to start with."
Surprise began sweating anxiously.
A wave of anger roiled inside of Spitfire's chest. "Is there or is there not an initiation for recruits?"
"Uh-well-um-I…"
"Answer. The. Question." Despite being bound inside her sleeping bag, Spitfire still looked like a formidable threat.
"Okay! You see…I…saw a chance to have some fun with you and yank your chain around a bit at the same time." Surprise giggled nervously.
Spitfire clenched her teeth. Her right eye twitched madly.
"But look on the bright side! Your flank and hips look amazing with all that fabric hugging your curves."
The entirety of Wonderbolt Academy shook harshly on its foundations. The walls and windowpanes rattled from the vibrations of Spitfire's enraged curses that rang throughout the hallways. The pegasus' booming death threats could've sent King Sombra himself running for the hills.
Surprise's ears flapped down as she lunged forward and resealed Spitfire's lips with the tape.
"MMHHRBUKKING LYHHNG PRVRRTED CHHKSUCKRR!!!"
Surprise reeled back in offense. "Sweet Celestia, you really gotta work on that potty mouth of yours! You're always so spitting mad!"
Spitfire growled behind her gag as her eyes flashed with the promise of revenge.
Surprise tapped her chin. "Spitting mad…" She gasped in realization. "Hey, I think we just found your nickname!"
Spitfire's eyes widened. "Dhnt. Yhh. DRRHE."
Her flying partner merely grinned slyly. "Oh, I do dare, sweetie. And just for your foul language, I'm adding an extra hour to your initiation."
"WHHT?!?!" Spitfire wrestled to break her forehooves free from her sleeping bag, but to no avail.
"This must be what you're looking for." Surprise grinned as she tauntingly dangled the key to Spitfire's locked zipper a few feet from her muzzle. "Heh. You look so cute and hot like this. Like some…angry, horny caterpillar."
"BHHK. YHH." A crisp outline of a scowl formed on Spitfire's gagged lips.
Surprise stepped closer and pressed a hoof on Spitfire's flank. The yellow-coated pegasus groaned behind her gag as she wriggled to free herself from her captor's hold.
"Hmm. Maybe I should put your flight suit mask on you." Surprise's voice took on a sultry tone. "Oh, buck yeah. That'll make things ten times sexier."
Spitfire's muffled screams echoed behind the closed doors of the locker room.

Rainbow Dash stared slack-jawed at her captain.
"And that's the story." Spitfire rubbed the back of her neck as her cheeks took on a shade of red.
Rainbow remained uncharacteristically silent.
Spitfire leaned dangerously close. "If you're having any lewd thoughts of me tied up in my sleeping bag, I highly suggest you banish them from your mind for the sake of your career."
Rainbow shook her head. "R-Right! Sorry, Spitfi-I-I mean, ma'am!!"
"That's better."
Rainbow chuckled awkwardly. "So…um…interesting story about how you got your nickname from Surprise."
"And the story of how we became marefriends," Spitfire added nonchalantly.
"Oh, yeah. I got that impression from how close you guys trained and talked together," Rainbow observed.
"Eeyup."
"Well…if Spitfire is your nickname, then what's your real name?" Rainbow then asked.
"You're really not gonna drop this, are you, Dash?"
The prismatic-maned pegasus shook her head.
Spitfire shrugged. "Okay, okay. My name is actually"


—I leave Spitfire's real name up to you ;)
—(I redrew the eyes because I really didn't like how they turned out in the last version. This revision feels more accurate to the show imo)