Now, there are some things that must be said about Spike before we continue.
Spike, as has been previously noted, was a dragon. A dragon of Equestria, to be precise. And as a dragon of Equestria, Spike possessed some unique traits. The ability to eat gemstones, a magical mutability influenced by his emotional state, flame-based magical capabilities.... All traits that had served him well at various points in his life. However, his most useful ability was, quite simply put, being more level headed then the ponies around him. Ponies, as mammalian creatures, had a relatively high thoughts per second ratio, where dragons tended to have a more relaxed and reptilian thought process. Granted, for most dragons that merely led them to keep their worries in the present and gather hoards for their own reasons.
However, Spike had endured one of the best educations possible in the nation he lived in, albeit indirectly and generally as an assistant to the primary student (herself neurotically obsessed with complete control over her skills and expertise ever since a long forgotten traumatic incident involving a cheese-based foodstuff in her infancy). Where most dragons were simply intellectually lazy, Spike was not only still young enough to scheme and plot but also educated enough to know--for the most part--what would and would not work. His emotional attachment to ponies was generally his primary motivator, another unique attribute among his kin, which meant that he would in general work to better their lives (especially that of aforementioned primary student who, it should be noted, hatched his egg).
"Hey Twilight," Spike casually greeted as he walked into the den. "Rarity just dropped by to look up some legal things."
"Oh?"
"Yeah." He chuckled for a moment. "Apparently she didn't know if Rainbow and Applejack could legally date."
"Huh."
With all that said, Spike was still a child and, to be entirely honest, sometimes overestimated exactly what info ponies could handle.
"Wait." The purple pony with the rare combination of wings and a horn pulled her gaze away from the reports she was reading, carfully setting them down so they would remain as organized as they were in her magical grasp. "Rainbow and Applejack are dating?"
"That is indeed what appears to be happening," Spike replied, obliviously walking across the room to find himself some reading material. "Well, that's what Rarity said anyway. And we both know how socially aware she is--although I'm a bit surprised she didn't realize that it was actually legal to date one's own gender--"
"Oh my gosh. This is--this could be bad." Twilight put her reports down, pushing herself into a standing position. "This could be very, very bad."
The young dragon had long ago learned not only how to detect panic in his employer/parent/sibling's voice, but also exactly what kind of panic and how much of it was present. This, for example, was the beginning of long-term panic over the potential personal results, which was odd since that usually only happened due to Twilight's own actions regarding herself.
"Okay... Twilight, you're doing that thing again. What's the problem?"
"The problem?! The problem is that Applejack and Rainbow Dash both have thrones in this castle!" Twilight started pacing. "If they engage in a public romantic endeavor, word will reach the local journalists and paparazzi. When they publish articles about the relationship--and they will, it's their job as well as being juicy gossip--some of those articles will make their way into the hooves of ponies that the nobles of Canterlot have sent here to quote unquote 'observe' the new princess--don't even bother trying to deny it, they exist because it's politically expedient and Celestia warned me it would happen anyway. This in turn will result in both an increased media presence from out of town journalists as well as societal commentary along the lines of all of us with thrones being set up for one another in marriage--perhaps even as one big herd! Don't you see Spike?! If Applejack and Rainbow date, everypony will expect me to date one of my friends!"
She paused. "Which, in and of itself wouldn't be that bad, I'll admit, they're not bad ponies, but I don't have any romantic feelings for them and besides I might need to marry a foreign dignitary for diplomatic reasons later."
Spike nodded slowly. "...so, just to be clear, your only objection is political."
"Well, political and personal, but yes. If there was a way for them to date without attracting attention--"
The many different bundles of information in the alicorn's head danced and twirled about, weaving and unweaving through the problem with an unnerving efficiency brought about by the many times Twilight had been forced to think quickly on her hooves. Actions were assessed and dismissed with the speed of a humming-bird's wings, right up until she found something that would qualify as an acceptable solution. To be completely fair, it might perhaps have been an acceptable solution if she was the only one acting on it.
Twilight's eyes widened, and she bolted straight up. "That's it! I know exactly what I need to do!" She galloped out the door without any further explanation, leaving behind a very worried dragon.
Spike held up a claw, considered his position, and finally gave a little shrug. "I should probably just be ready to help clean up the fallout, I don't think I'm going to be able to stop this train wreck." He tapped his chin thoughtfully. "Hmmm. Should I send a letter to Celestia now, or should I wait...? I'm going to wait. Right now her presence might just make Twilight panic worse."