Be Santa Mare. You should be glad that so many ponies have been good these past years. And you are, but it also means that you have a huge stockpile of coal with nowhere to go. You stopped your parasprite minions from mining the stuff years ago. You needed the extra labor to keep up toy production.
You sigh, stretching out the ol' withers and flank. Well, it's that time of year again, better check the lists. Nice list is literally a mile long. Yeah, you're only checking it once. A parasprite bumps into you, helpfully carrying a little slip of paper. Naughty List, blanks as alw-
Hold up. Who is Anonymous?
Be Anonymous, pretending to sleep. In your time in Equestria, you've noticed ponies are unbelievably gullible. You feel a little guilty about the"gotcha nose" incident, and that time with the thumb trick. Luckily, you convinced them it was all a dream, so now it's Luna's problem. Which brings you to now, where you are lying in wait for whatever Santa equivalent little horse land has.
Stocking?
Hung like a horse.
Tree?
Twinkly and ribbonned up.
Plate of cookies and glass of milk?
The absolute best chocolate chip cookies you can make from the recipe on the chocolate chip bag. And an oatmeal raisin cookie, because you can.
Milk in a wine glass.
Bed?
You are camped out by the fireplace in a sleeping bag, with your trusty teddy bear. Time for your flawless acting.
"Honk, choo, honk, choo."
That's the sound of sleep, no mistake. After a few minutes, you hear the telltale sound of hoofsteps on the roof. Showtime.
You hear rustling from the fireplace, then a thump. A pause.
"I know you're awake."
What a nice, mature female voice. But she's bluffing.
"I'm not bluffing."
Damn, she wins this round. You make a big show of yawning and rubbing your eyes. Looks like Santa Mare is something of a silver cougar, with the toned and slender body of a Canterlot socialite, under a loose red cloak that stops just short of the curve of her flank. Nice.
"Nice to meet you, Santa. Would you like some milk and cookies?"
She smiles wryly.
"Don't mind if I do. Now let's see..."
Silvery light plucks the oatmeal raisin cookie from the plate.
"Oatmeal raisin, really?"
"Well,"
"It's nice to have some variety, but who do you think you're fooling?"
You have the distinct feeling that you may not be on the nice list anymore.
"It was worth a try. How is it, by the way?"
She takes a bite, her eyebrows rising.
"This actually pretty good. Do you have more?"
"Uh, yeah, just a moment."
You retrieve a plateful from the fridge, setting it before Santa. She eyes the glass of milk.
"I bet you even jizzed in the milk, eh?"
What? She lifts it in her magic, swirling the glass contemplatively. You feel obligated to protest you innocence in this particular case.
"Actually,"
Santa Mare tilts her head back and drinks it all in one gulp.
...
She then looks at you with half-lidded eyes, licking her lips.
"I have a proposition for you, you naughty colt."
You are standing at attention, in all sorts of ways.
"What do you have in mind?"
She takes a sinuous step towards you.
"I have a lot of coal I need to get rid of, and exactly one person on the naughty list."
Santa takes another step towards you, her flank shifting hypnotically.
"I'm going to need you to stay on that naughty list, and get coal every year."
Her cloak unfastens, slipping to the floor. She rears up, placing her hooves on your chest.
"But don't worry."
She nuzzles your neck.
"We'll be naughty together."
You grin, grabbing her by the haunches.
"You give me coal, I'll give you diamonds."
She hums sensuously, her plush rump shifting in your hands. Her eyes gaze at you with a terrifying hunger.
"It's such short notice, it's fine if you don't wrap your package."
And that's how you became Father Christmas in Equestria.