The young Shining Armor sighed happily as she accompanied the jumping, frolicking, and overall ecstatic unicorn-filly-sister Twilight Sparkle through their favourite park in Canterlot, carrying their picnic basket on his back.
It was a day they decided to spend together, like many others. With practiced ease , Shining levitated the chequered blanket on the grass and set up the meal for the two of them, while Twilight was busy staring intently at a cricket on a nearby tree.
"Did you know that crickets chirp by rubbing their wings together?" She explained, eyes full of wonder.
Shining chuckled. "Do you think pegasi could manage to make a sound like that?" He replied. He knew it felt a bit like a stupid question, but he always liked seeing Twilight's mental gears spin into motion on a new problem, like she was doing now, hoof on chin, brows furrowed.
"Hmmmm.... The frequency of the sound would mean... but then the wing hardness... factor the square-cube law... lack of chitin...mmmm... nope!" She chirped. "They can do it with their voices, but their wings wouldn't be able to."
Shining just smiled in response. "Here Twiley, I've got your sandwich." Dandelions, roses and mayo, her all-time favourite.
She skipped happily back to the picnic blanket, snatched the meal in her forehooves and dug enthusiastically into it.
Shining was slower and more contemplative in his eating. "Twiley... Have you seen the guard patrol just before?"
"Yup! Marching in formation through Winter Plaza, punctual and polished as always!" She nodded, speaking through her full mouth.
"I know... They really look great, don't they?" Shining mused.
"Yeah, and they look like a perfect fit for my Big Brother Best Friend Forever to join in!" She blurted in.
Shining Armor jumped to attention: when did Twilight catch on to that? "Twiley... How do you-"
The filly gulped hastily. "Are you kidding? I've seen you always admiring and talking about the guards of Princess Celestia or the Castle rounds or the patrols or the skirmishing training- You're just an open book to me, brother," she concluded triumphantly, adding a sizable bite of her sandwich to the celebration for her deduction.
"Yeah... I guess I do go on about them a little..." He conceded, hoof rubbing the back of his neck.
"And I know for sure that, with the current ratio of time spent training to time available, you'll be able to enlist in the Royal Guard in no time!"
"Really?!" Shining was all ears; Twilight did NOT throw hyperboles around. When she said something, she meant it. "Why do you say that?"
"I've been studying you," she said, plain and innocent as the filly she was. Oh yeah, that was Twiley alright. "I've ranked your attentiveness, observance, protection factor, magical reflexes, AND fitness-"
Shining did a double-take. "Wait- Is that why you kept throwing toys and plates and quills around the hou-"
"-AND my results point to a perfect 10/10 score, as clearly shown in the-" It was Twilight's turn to interrupt herself, pointing hoof hung in midair. "Oh... heh, I guess the proper data recollection and graphs and pie charts will have to wait until we get home, hehe." Twilight rubbed her hooves together, in slight embarrassment.
"That's OK, Twiley- Please continue," Shining encouraged, nuzzling Twilight; this was too interesting to wait.
"Well, alright- As I said, the cross-referenced and compared graduations show a top result in the combined ranking of defensive capabilities of the ponies across all of- Well, all of the books I could find, really, but that's a whole lot! I've managed to gather a pool of two thousand units and extracted the relevant statistics by fitting them on standard sca-"
"Whoa, you're losing me, Twiley," Shining admitted, hoof massaging his temple; his adolescent mind had not been in the least prepared at school for this kind of scientific onslaught.
"Um, I suppose I'll arrange an abridged version at home- but as a conclusion, you're the best! The best BBBFF I could ever ask for, AND the best candidate for being a Royal Guard and protecting Princess Celestia!" She declared, full of enthusiasm.
"Well, I'm not sure the Princess keeps them all that clo- Wait, do you really mean THE BEST?!" Shining was absolutely shocked.
"There's really no one like you, Shiny," Twilight said, looking right in his eyes, sniffing a bit before continuing. "I know, I checked. The job of a Royal Guard must take a l-lot of hours each day on duty," Twilight was starting to stutter and struggling to keep talking, "But yesterday, as I-I read all the gr-great things all the g-guards have done, I realized it doesn't- It doesn't matter."
Her eyes were getting moist, as she kept her gaze on her brother, hooves leaning on him. "Even if it means I'll ha-have to share my BBBFF with the rest of Equestria, that m-*sob*-means I'll have to do that sacrifice for the better of all ponies.
"There's really no one *sob* I-I'd rather have watching over me, and that means it's best if you do that with as many- as many pones as you can."
This show was too much even for the tough show that was Shining Armor. Eyes watering, lip trembling, he swept his little sister in his tightest hug, shuddering with the power of the words she had delivered. To hear your lifelong aspiration confirmed by your best sister... His brain was swimming; it felt more like a dream to him in this moment. At the same time, he knew she had to be completely right. That he felt just natural in the role of big brother and protector. That he'd rather do this all his life rather than anything else.
A few minutes later, when they released the hug, Twilight noticed in ecstasy that a little something had appeared on her brother's flanks.