//------------------------------//
// FredMSloniker's Best Practices (Irrespective's "Lavender Screen of Death") 
// Story: Never the Final Word (Vol. 2) 
// by FanOfMostEverything 
//------------------------------//

"Honestly, you should have set this all up much sooner."

Princess Celestia scrunched her muzzle, peering quizzically at the unicorn colt who reminded her more than a little of Twilight Sparkle in both color and temperament, before turning her attention to Sunset Shimmer. When she had reached out to her former student in hopes of—to put it  bluntly—having a backup plan in case Rarity crashed Twilight Sparkle for a third time, she hadn't expected Sunset to drag one of her classmates through the portal, introduce him as the 'real techhead', then go into a huddle with him and the other two while seeming to forget Celestia even existed.

The two of them had put Twilight to rights, more or less. At the very least, Twilight hadn't crashed the moment Rarity spoke—again—and though Celestia wasn't sure an animated lecture on the proper construction of dark magic spells was  entirely called for, or for that matter what relevance underwater research facilities had to dresses, Rarity had looked less 'panic-stricken' and more 'stuck in an awkward social situation', which had been an expression Celestia had seen on the faces of those Twilight talked to for many years and was thus prepared to accept as normal.

Now, however, Twilight was dozing softly at one end of a spell diagram, three parallel lines diverging into what could be called an erupting volcano if you squinted, with three creatures sleeping at the three points of its 'base'. Sunset Shimmer was one of them, which made sense, and Starlight Glimmer was another. The third, however, was neither unicorn nor alicorn—not even a pony, for that matter—and Celestia wasn't  sure what to make of her inclusion.

Celestia turned back to the colt as he finished giving instructions to Princess Luna—what he could  teach her about dream magic, Celestia didn't know, but vaguely treasonous grumbling aside he did seem to know what he was talking about—and put on her third-best expression of polite, if somewhat bewildered, serenity. (Her first-best such was to be kept locked away so long as Equestria remained at peace, and the second-best was in the wash.) "I was wondering if you might explain why all three of them are necessary for this," she said, flicking her head at the trio. "Especially her," she added, gesturing at Ocellus, who had looked equally confused while awake. "Wouldn't it be better to have a third unicorn, or at least a changeling with more—"

The colt rolled his  eyes behind his thick-lensed glasses. "Look, you don't just stick a  copy of important data in your sock drawer and call it safe." (Celestia made a mental note to review the security of her sock drawer.) "There's a very simple rule to follow. Three copies." He pointed at Starlight. "Two formats." He pointed at Ocellus. "And one—" he pointed at Sunset, "stored off-site."