As a big sister figure, Rainbow Dash had by now gotten used to the idea that she would have to step in sometimes when the pony she'd taken under her wing needed help. It was expected of her and she had already done so on numerous occasions when necessary.
So at first the cyan coated speedster didn't think anything was too out of the ordinary when she swooped by the CMC's clubhouse and spotted Scootaloo curled up in a corner, sobbing gently to herself and away from prying eyes.
Landing just outside the door the pegasus rapped a hoof against it. It swung open with little effort and Rainbow trotted inside. It was now that she got a chance to see just how out of the ordinary things were.
Scootaloo's eyes were reddened, a clear sign of crying that had gone on for a very long time. Several tissues lay balled up nearby, carelessly discarded without a second thought. Most tellingly of all, however, a small puddle reached down to the floor boards nearby. And Scootaloo's sobs only sounded louder with each passing second. Whatever it was that she was upset about clearly troubled her on a deep level.
But regardless of circumstance Rainbow knew it was up to her to put her big sister role to good use and try to find out just what had happened. Plus, it always tore her up to see her number one fan upset for any reason.
"Hey, squirt," The cyan coated pegasus gently called, attracting Scootaloo's attention for but a moment. "What's the matter? Why are you crying?"
"It's nothing!" Scootaloo protested a bit too loudly, it only served to make her big sister more concerned and more prying, which was the last thing the filly wanted at the moment.
Rainbow shook her head. "Doesn't look or sound like nothing to me. Even Apple Bloom and Sweetie Belle are concerned, they're the ones who told me you were crying to yourself in here. When I asked them they said you wouldn't tell them anything."
"Because it's not their place to know, they wouldn't understand," The orange coated pegasus complained and turned her head. "Just leave me alone! I want to be alone!"
The still relatively new Wonderbolt refused to obey. She wasn't the Element of Loyalty for nothing, she'd never turn her back on a pony in need if she was certain there was something she could do to make it better. In fact, this situation reminded her an awful lot of Twilight's breakdown after the EEA had shuttered her school of friendship. Though something told the mare that tough love was not an option here, despite what Starlight might think.
All the same Rainbow didn't want to pry. Much like Aunt Holiday she preferred to let Scootaloo tell her on her own terms when she felt ready. But that didn't mean the cyan coated pegasus couldn't still try to nudge the conversation towards the subject of importance. If she waited for Scootaloo to tell her that could take ages, perhaps even longer.
"Come on, kid, you know you can tell me. I promise, you blab to me and this doesn't have to leave the clubhouse," Rainbow offered. "I want to help you, Scootaloo, but I can't do that if you won't tell me what's wrong."
Scootaloo appeared to be tempted by the offer, Rainbow Dash did have a pretty good track record for keeping promises and secrets. After all she'd managed to hide the fact that she had parents for years, and if she'd had it her way she likely would've continued to keep said fact a secret. But another part of her was still convinced that even her big sister wouldn't be of help in this situation.
"You wouldn't understand." The filly protested with a shake of her head.
Rainbow bent down, lowering herself to Scootaloo's level so that she could make eye contact. "Try me."
"I said it's nothing. Why can't you just leave me alone already? I'll be fine." The orange coated pegasus protested and turned her still reddened eyes away, refusing to look her idol and big sister in the face.
"If it's about your wings you know we already talked about this," Rainbow said with a sigh. "It doesn't matter if you fly or not, you're awesome just being you and that will never change."
"It's not about my wings, I've accepted the fact that they may never get me off the ground even though I'm sure they will someday," Scootaloo commented in a raspy tone of voice. By now the non-stop crying and sobbing had taken a toll on her vocal chords. "This is something far greater than my wings, even Auntie Lofty says there's nothing wrong with them."
A small sigh of relief escaped the elder pegasus' lips upon hearing that. She was still not entirely sure what the reason was for Scootaloo's inability to fly and remained at a loss as to what to tell the filly other than the fact that nopony seemed to know for sure whether or not she would truly fly. So at least that delicate situation was taken care of.
That still left the mystery of what was the source of the younger pegasus' sorrow. If not the wings then what else could it be? There didn't seem to be any signs of injury, and Rainbow could've sworn she'd spotted her little sister's scooter outside the clubhouse, still in one piece and without a scratch on it. So it couldn't be either of those things. And it wasn't a friendship problem because if it had gotten to the point where Scootaloo's fellow Crusaders were worried the map would've taken notice long before then.
Then all of a sudden, a realization seemed to strike the cyan coated speedster square in the snout. How come it had slipped her notice until just now? It was kind of late for Scootaloo to be out and about, after all it was a school night. Aunt Holiday and Auntie Lofty were not overly bearing on curfew from what Scootaloo had said, but they had given her an earful that one time she'd stayed at Rainbow's without telling them where she would be.
Come to think of it, shouldn't Scootaloo be at home by now? Maybe that was the problem, something had happened with Aunt Holiday and Auntie Lofty. Of course, that had to be it! With this stroke of inspiration, Rainbow finally asked. "Hey, Scootaloo, do Aunt Holiday and Auntie Lofty know you're here? You're usually not at the clubhouse at this time of evening."
At the mention of her aunts the filly appeared to freeze as though a chill had suddenly swept past her. That was a telltale sign for Rainbow's trained eyes, Scootaloo only ever reacted that way if something was troubling her greatly and she didn't want to admit to it. So the cyan coated mare continued to pry. "Did something happen between you and your aunts? Are they okay?"
Scootaloo appeared to reluctantly nod her head. "Yeah, they're fine. It's totally stupid and pointless and I bet they're already out looking for me because of it."
"So, aren't you gonna tell me what it is? You know I don't like seeing you upset." The off-duty Wonderbolt not so subtly pleaded with her number one fan and little sister.
But it appeared to achieve its intended effect, for with a sigh Scootaloo confessed between sobs. "Aunt Holiday and Auntie Lofty mentioned that my grades have been slipping lately, and that they want me to start cutting back on the Crusader activities and were gonna talk to Twilight about reducing my time as a friendship tutor. So I got mad at them and I... I..." She trailed off, unable to bring herself to say anymore.
"You what?" Rainbow encouraged as she reached out a hoof and started stroking Scootaloo's back to calm her down, hoping that such an act might motivate her to open up.
"I... I said... said I... hated them," The filly choked out. "I said I hated them and that they were not my parents and I didn't need them telling me what to do."
"Whoa! That was... pretty harsh." Was all Rainbow could bring herself to say.
With a sniffle Scootaloo seemed to agree with her big sister's assessment. "Yeah, it was. I didn't mean to say it, I just got so mad and I couldn't think straight."
"So you ran away because of that?" Rainbow questioned, Scootaloo confirmed it with a nod.
"I'm sorry you had to be bothered with all of this," The filly apologized as her tears slowly began to stop. "I never wanted you or anypony else to get involved. But now my aunts probably hate me, or think that I'm ungrateful."
But the cyan coated mare shook her head at the statement. "Squirt, I know your aunts and I know they know you're better than that. They're not going to suddenly think you're ungrateful because of one outburst, I'll bet they're worried sick about you," And then after making sure that nopony else was around, she pulled her honorary little sister close and reassured her. "You saw how I got into a fight with my parents at the Wonderbolts Academy, right?"
"Yeah, I remember that," Scootaloo nodded. "I couldn't believe it when I saw it."
"Well, did my parents suddenly stop loving me because of that?" Rainbow questioned.
Scootaloo hung her head in shame. "No." She admitted.
The elder pegasus simply nodded in response. "Exactly. Family is still family, and one argument isn't going to change that. I'm sure Aunt Holiday and Auntie Lofty don't think any differently of you for that outburst. And if you come back to them and apologize, I'm sure all will be forgiven."
"You really think so?" Scootaloo nervously asked as her crying finally stopped. Several red rings had formed around her light purple eyes.
Her big sister nodded and even lightly ruffled her mane. "I know so. And if they're still mad they can take it up with me. Now come on, let's get you home before Celestia's sun sets. I think Holiday and Lofty have worried long enough."
It was nearly sundown when Rainbow brought a recently tear free Scootaloo back to the front step of her house. Waiting anxiously on the steps were two mares of relatively similar size. One was an earth pony mare with a sea green coat, eyes the same red color as a sunset, a wavy blonde mane and tail, and a cutie mark depicting a red bow with a yellow star in the center. She was wearing an orange necktie. And the other was a slightly taller (and significantly sturdier) pegasus mare with a coat the same light brown as sand. Her eyes were the same blue as Rarity's, her wavy mane and tail sported locks of dark blue and pinkish-purple, and her cutie mark depicted two pink balls of yarn with two dark blue puffs.
Of course these two mares were easily recognizable to Rainbow Dash and Scootaloo, they were Aunt Holiday and Auntie Lofty. And the two of them looked incredibly relieved to see their niece safe and sound.
Auntie Lofty was the first one to approach Scootaloo, quickly wrapping her in a tight hug. "Oh thank goodness you've finally come home, slugger! Holiday and I were worried we'd have to call out the royal guard just to find you." She exclaimed.
Aunt Holiday only giggled. "I told you, Lofty my dear, everything would be just fine. There are lots of places a filly like Scootaloo could go if she needed a safe place to spend the night," Then she approached Rainbow Dash. "Thank you so much for locating Scootaloo for us though, I know she's in good hooves with you."
"Happy to help, ma'am," Rainbow saluted. "Anything for my number one fan and little sister," And then she cleared her throat. "Now, Scootaloo, I believe you have some things you'd like to say to Aunt Holiday and Auntie Lofty?"
But Rainbow needn't have encouraged, for the filly looked into both her aunts' eyes and the tears started to flow anew. "I'm so sorry Aunt Holiday and Auntie Lofty, I didn't mean to say all those things that I said. I'm not ungrateful, I promise I'll get my grades back up."
"Of course you will, Scootaloo," Aunt Holiday smiled as she lightly stroked her niece's mane with a hoof. "And Lofty and I know you're not ungrateful. After all, we raised you to be better than that. One little outburst isn't suddenly going to make us doubt our favorite little filly in the whole wide world."
"Even so, don't ever run off on us like that again," Auntie Lofty lectured. "You scared Holiday and I half to death."
Scootaloo looked down at the ground. "I know, I know. And I'm sorry. I just got mad and lost my temper," Then she reluctantly asked. "Am I in trouble?"
"Oh yes, you certainly are I'm afraid," Holiday scolded with a serious gaze. "You're going to be grounded for the rest of the week, young mare. I'm sure you've learned your lesson, but Lofty and I want to make sure you don't think of running away from home like the way you just did. Celestia knows you make us worry enough as it is with your daredevil stunts and constant Crusader activities."
"But we can discuss the details of your punishment tomorrow, and we can also discuss walking back your adjusted curfew just a little," Lofty added. "For now though it's getting quite late, I think it's time to call it a night."
Scootaloo reluctantly nodded. "Okay Aunt Holiday, okay Auntie Lofty."
Rainbow simply watched as the three went inside, then breathed a sigh of relief and wiped the sweat from her brows. Being a big sister was harder than it might seem to most ponies.
Author's Note
I've already done a lot of Scootaloo fics involving headcanon parents, so I wanted to do something different and do something with what family has been established of her in canon so far.
Aunt Holiday and Auntie Lofty have been around since the third Ponyville Mysteries series book "Riddle of the Rusty Horseshoe". The basic details are that Holiday is an earth pony and is Scootaloo's dad's older sister, while Auntie Lofty is a pegasus. Holiday is established as being slightly more protective of Scootaloo, but also lets Scootaloo tell her things when she's ready. Meanwhile, Lofty is established as far more concerned about Scootaloo's daily life and never lets things go without an answer. It is also established that Holiday calls Lofty "dear".
They have also been mentioned in the fourth Ponyville Mysteries book, in which Auntie Lofty is revealed to be the sterner of the two and the one who lectures Scootaloo on safety. And they have also appeared in the third Ponyville Mysteries comic from IDW, which is where their designs come from as can be seen here: 
