It goes about like you'd expect
Donald Trump grabs Princess Celestia in the Pussy
Admiral Biscuit
The meeting took place in Canterlot Castle, in the Grand Hall. Hundreds of ponies gathered in the galleries, eager to witness this historic occasion. Applejack was there, too.
It was the grand trade summit, held every dozen or so moons, and representatives and shysters from nearly every friendly nation came to discuss trade deals with their peers.
The initial reception in the Grand Hall was not where the actual business was conducted, of course, although none of the rabble knew it. That meeting was just a formality, a way for ponies to publicly be seen meeting other species and getting along with them. There were shaggy yaks, slick-looking goats, llamas in hats, and even an orange creature that everypony assumed was somehow related to a monkey or an Oompa-Loompa. They hoped it was the latter, because last time Willy Wonka had made a trade deal, he had literally turned a river into chocolate, and per the deal, it had turned back just before everypony had gotten sick of chocolate.
After obligatory greetings, insincere speeches promising untold economic benefits and an increased standard of living for every mare, stallion, and foal throughout all of Equestria, the trade delegates all made their way back out of the Grand Hall, followed by Princess Celestia and her retinue of guards and standard-bearers.
Most of the ponies in the gallery went home as well—they'd seen what they wanted to see, and they could go back home and tell their lovers and friends about that time they'd bumped hooves with a yak, or speculate on how soon every-flavor jawbreakers might show up at the nearest confectionery.
• • •
Dinner was boring, and everyone agreed that was for the best. Nobody wanted a repeat of the lutefisk incident, which had ultimately set back trade with the griffons a century or more. Therefore, the menu had been carefully selected to not offend anyone, be they herbivore, carnivore, or omnivore. Which meant that formal castle dinners generally consisted mostly of wine and dessert.
They also had pizza, because one can put damn near anything on a pizza, and there's always something for everyone to like on a pizza. Heck, there are even dessert pizzas. And Chip Cow's Pizzaria not only delivers throughout Canterlot, but every Princess-size pizza comes with a free order of cheezy bread with complementary marenara sauce. Ranch is also available for a nominal surcharge.
After dinner was over and the ice was well and truly broken, everyone went into the Royal Ballroom for the Trade Gala. What happened out on the dance floor wasn't a dance in the sense of couples actually performing a series of highly choreographed moves with musical accompaniment; rather it was a delicate battle of wits, where every trader would move to gain the most personal advantage while giving away the least.
First offers were given, briefly considered, then countered, every one just as well choreographed as a pavane.
Donald Trump, who was probably not actually an Oompa-Loompa, was perfectly at home here. He was the master of the art of the deal after all; his book said so. So did everyone else, and they were really great people. He had the best people.
Donald had already scribbled down notes of Twilight Sparkle's speech, just in case Melania had to give another convention speech or something. It was always smart to be prepared. So now he was free to mingle and make deals that would make America great again, or at least line his own pockets.
His first deal had been a stunning success—he'd managed to convince a pair of fast-talking unicorns in straw boater hats that he would be willing to pay a team of pegasi window-washers top dollar for washing the windows at Trump Tower, although once they arrived in New York, he planned to actually pay them in hay bales and if they complained, deport them right back to Equestria. The two—he didn't quite catch their names, but they were brothers—had gleefully taken the rubber check he'd given them as a finder's fee and had wandered off elsewhere. It was only later that he would discover that the source of their glee wasn’t the rubber check, but the fact that Flim had lifted his wallet while Flam was negotiating.
Donald turned around looking for his next mark and found himself face to face (in a manner of speaking) with Princess Celestia's perfect posterior.
He couldn't help but look and how firm her rump was, or how when she moved her tail away her delicate pink nethers looked very much like an inverted exclamation point. Trump's motto was when you're rich you can get away with anything, so he popped a tic-tac in his mouth and reached over and grabbed her right in the pussy.
• • •
Much has been written about Princess Celestia's magical abilities, or the lack thereof. It's speculated that she can call down the fury of a sun, reducing anypony or anything which displeases her into molten slag, or perhaps even simple atoms. Others believe that she's a paper tiger, that her adoring little ponies take care of all her problems for her, and maybe she doesn't even raise the sun. Maybe it just raises itself without any help from her at all.
Less has been written about her physical abilities, which is a shame.
The craftsponies who had made her golden hoof-boots all those centuries ago had wanted to make something which was not only fitting for a princess, but which would also last a lifetime. And while mere gold might have sufficed for one of their lifetimes, they all knew that one of Princess Celestia's lifetimes was dozens of theirs, so at the very heart of each hoof-boot was the finest Damarescus steel that anypony had ever forged.
Princess Celestia lashed out with both hind legs simultaneously, her gold-plated shoes landing squarely in his stomach with horrifying precision. Her size sixteen steel shoes struck solidly enough to actually leave a hoof-shaped bruise on his liver, although fortunately nobody could actually see that.
Her punt was the envy of every hoofball fan present, and one of the minotaurs actually started clapping as the orange one sailed across the ballroom. Unfortunately, his trajectory would intersect with the dessert table; specifically, if nopony did anything in the next half-second or so, Donald Trump and the Marzipan Mascarpone Meringue Madness would become one.
Princess Celestia utilized the one spell which she unquestionably knows, and one blast of Harmony™ later, Donald Trump ended his flight on the lunar regolith, sliding to a stop in a distance which was six times greater than he would have skidded had he remained on-planet.
With a smile returning to her face, Princess Celestia declared that hereafter no more Oompa-Loompas would be invited to trade meetings, and then began to slice the cake.