A/N - This is the kind of stuff one comes up with when they spend too much time over-analyzing insignificant parts of a show... A picture I saw on Ponibooru brought this little gem to my attention.
The Royal Canterlot Wedding had been everything the ponies of Equestria ever dared to expect and more. Shining Armor was the pinnacle of dashing, heroic stallion-dom, lovingly sashaying along the dance floor with his bride, Princess Cadence, who in turn was receiving fanciful glances from mares and colts alike, envious of one or the other. The festivities, the spotlight on the happy couple, and the amorous gazes they shared would be the talk of the country, and an event not soon to be forgotten.
Many songs had been requested that night, some light and romantic, others with a good electro-pop bounce or somewhat heavier bass. The array of musical styles was diverse enough to satisfy the tastes of any pony in attendance, from the stuffy elites with their classical favorites to the younger, more gritty generations, though the lack of power ballads was mildly disappointing. What good is a freakin' wedding without heartfelt power ballads?
One of the ponies, however, seemed to enjoy anything and everything the DJ had to offer. She may not have been as lively as Shining Armor and Cadence, or some of the young colts who seemed to be trying to turn on their heads to some of the more rhythm heavy tunes, and failing miserably, but in her own subtle way, she never had this much...fun...in over a thousand years.
Rainbow Dash was the first to notice it. The pegasus with a multicolored mane watched as her head would lift up and dip down sharply to the time of the music. It looked a little...mechanical at some points, and she was slightly off beat to most of the tunes, stubbornly trying to maintain her own tempo in the face of some of the faster songs, where other ponies would be flipping around, tapping their hooves, and shouting the lyrics. Dash went over to inquire about this new dance move that she had never witnessed before.
"Hey Princess Luna, that's an awesome move you have there! What's it called?"
The princess of the night regarded the blue pegasus with a cool look, seemingly trying to concentrate on the dance she was performing.
"Ah, Rainbow Dash, THIS is an ancient dance maneuver, performed at every elite social function, that we aptly used to call...THE ROYAL HEAD-BANG!"
As the dark mare demonstrated the nuanced workings of the routine, Dash couldn't tell if she was supposed to be incredibly impressed at the unfamiliar move, or perturbed that such a simple looking stunt was so widely revered and performed in the distant past.
"So uh...is this the only dance that ponies used to do back then?"
Princess Luna stopped again for a moment to converse with the element of loyalty.
"Nay Rainbow Dash, there were certainly other forms of physical entertainment at functions such as these, however, the Royal Head-bang has been passed down through multiple generations. IT IS TRADITION!"
Luna shouted the last statement a little more forcefully than Dash was comfortable with, as she wanted to punctuate the authenticity of this maneuver, but she continued listening as the night princess spoke.
"It was also the only dance routine approved by the venerable Starswirl the Bearded! He used to dominate social functions in the courts of Canterlot with this time-honored move!"
Celestia was listening in on the conversation and coughed to herself, "That's because Starswirl was a horrible dancer. He was, as they say now, a girl repellent..."
If Luna had registered the whisper at all, she ignored her sister's quips, staunch in defending the dedication to tradition that the brilliant pony showed in his time. With a diamond-shod hoof waving in the air authoritatively, Luna encouraged Dash to join in on the act.
"Come Rainbow Dash, perform the Royal Head-bang with your princess, and take part in a tradition that is older than even myself!"
Once again, Luna went back to what she had been doing before, giving the pegasus a blueprint to follow. Timidly at first, mainly because she felt a little embarrassed about doing it, Dash started pulsing her head up and down to the beat of the next set of pop songs, watching Luna as she seemed to spur Dash on with her own "head-bang".
"Good, good, that is how it is done! Watch your posture though. Stand straight up, and put more neck into it!"
The princess was pleased to finally be able to show another pony the virtues of fine culture, as the suggestive dances of her subjects were mildly offensive and certainly could not be any respected styles of art in this day and age. Dash seemed mildly uncomfortable as Luna gradually made her rock her head back and forth harder, as was the "proper" way.
"Geez Princess, I'm going to snap my neck at this rate!"
Dash was furiously bobbing her neck up and down in similar motions as the night princess, feeling a little dizzy with a migraine headache coming on. Luna seemed particularly unfazed as she too matched Dash's speed, albeit without the pain.
"Nonsense Rainbow Dash, you only need to exercise your neck muscles more! It is because of how taxing the head-bang is on one's body that ponies will line the streets for miles around to witness its graceful simplicity!"
It was very taxing, alright, and Dash was getting off beat further as she could hardly raise or lower her neck after almost five minutes of the grueling motion. Although Luna was also pretty horribly off tempo, only because of her stubborn need to make her own, she chided Rainbow Dash like any other aerobics instructor might.
"Rainbow Dash, you must stay on the beat. On the beat, like this! In my day, we used to dance this way for hours on end!"
Luna's haphazard pulses weren't helping Dash's situation one bit. After a few more grinding ups and downs, Rainbow Dash fell in a heap to the grassy floor, grasping her pounding brain in her hooves.
"Ooooh..." Dash felt like a vice was pushing around her head.
"Worry not Rainbow Dash," Princess Luna looked upon her sympathetically, "It is always quite trying the first few times you perform it. Diligence is the key! One day, you might even be as adept at the Royal Head-bang as your princess, given lots of practice!"
Dash was holding her head and her stomach, finding out that all that activity after drinking a gallon of fizzy soda was not the brightest idea on her part.
"Um...thanks Princess, but I think I'll just stick with something a little more...modern for now..."
Luna was a tad upset at the rejected offer, but waved her off with regal cordiality nonetheless.
"Oh well, I suppose not all ponies are ready to brave the rigors and intricacies of this, the Royal Head-bang! I do so hope you will change your mind and join me again one day!"
"Sure...Princess..." Dash started crawling off to get an ice pack for the swelling pressure assaulting her temples, "some other time..."
As Dash shuffled on her stomach to the nearest bathroom, no doubt the dizziness and nausea had gotten to her, Princess Luna sighed in remembrance of the parties she had attended over a thousand years ago, where this move could've practically been the new dance craze of the time. She certainly liked it, but didn't know that many other ponies with the fortitude or interest to partake in the dance.
"I shall keep this sacred maneuver alive, and one day, it will spread across the continent, reclaiming the days of its past glory!"
Motivated by her own words, the princess of the night went back to dancing along with the others as before, head-banging even more fiercely now than ever before.