Present time.

“Twilight, do you really think it’s wise to do the training inside?” Celestia wearily asked.

Twilight regained her focus and cleared her throat.

“Well… Considering you just made a gigantic hole in the castle’s side… we really should move this somewhere else.”

The young alicorn’s idea for a little warm up (smacking a punching bag with as little force as possible) produced an unexpected result in the form of a now VERY clear view of Canterlot City.
Well, unexpected for Twilight at least.

One might ask why Celestia wouldn’t just use her magic.
Well, that had indeed been Twilight’s first suggestion, but Celestia reminded her that using normal magic, like levitation, was safe but not suitable for handling mighty foes.
On the other hoof, using the Sun’s power to fuel her magic would be strong enough to defeat every major villain but would also most likely incinerate the atmosphere…
The strength of a sun-powered hoof slap might still be an unpredictable weapon of mass destruction but at least it didn’t usually mean more than one or two new ravines. A dozen tops.
Hopefully, the training would reduce the damage.
In any case, Twilight agreed, that using the hooves was preferable to a blazing Armageddon.

But let’s get back to our story...

“Twilight, I already told you fifteen times that you should reconsider this whole thing.”
Celestia pointed at the humongous gaping hole.
“As much as this gym needed a proper window… I think this undertaking will turn out too costly. Now I’ll have to calm down the citizens of Canterlot.”

Twilight, who (luckily) had been standing further away, teleported in front of her mentor.
“J-Just a minor setback! Leave the collateral to me!”
She quickly summoned a quill and a piece of parchment, wrote some instructions on it and sent it magically away.
“I’m positive that Spike will do an excellent job!”

“Spike?! Why don’t you let me handle the issue? After all, I am the one responsible…”

“Nuh nuh nuh nuh nuh no! I won’t let you off the hook that easily, Princess.”

Celestia’s ears dropped. Her hopes of getting away from the whole ordeal crumbled.
“Oh… You’ve got me.”

Darn it! For the second time today, one of my bluffs has been called out! Well, it IS Twilight Sparkle I'm dealing with here, one of the smartest ponies in existence. But with all that intelligence, why can't she see how futile and dangerous this endeavour is? She must have a lot of pent up anger because of all the struggles I've sent her through. For now, it might be better to play along for damage control and to not infuriate her any further. After all, I have certainly asked a lot of her...

The diarch sighed.
“I still have my doubts about this whole plan of yours, but fiiine... Where should we go?”

“How about the middle of the city?” a disembodied, snarky-nasal voice proposed.

Realizing immediately who it was, Twilight groaned.
“What are you doing here, Discord?”

With a flash of light, Discord, clothed in a training suit, appeared in the middle of the gym.
He was unusually muscular and was smugly lifting a huge dumbbell.
“Well, I was sensing some excellent chaos happening here! You don’t think I’m gonna miss out on that, Sparkles, do you?”

He looked at the hole, then at Celestia.
“What’s the matter, Celly? Taking out your anger on punching bags for being one for every villain?”

Celestia didn’t seem to care much about the remark, but Twilight grumpily turned to her mentor.
“See? That is exactly what I was talking about! You got defeated only one time and unfairly captured three times during your whole over-a-thousand-year life and now EVERY stupid meanie calls you weak!”

Discord huffed and swallowed his dumbbell. Then he turned to his normal form.
“Stupid? Me? Au contraire, dear Twilight! I am a genius! Do I have to remind you how I outwitted you all in the maze? Oooh, how embarrassing… for YOU! HAHAHAHA!!!”
He threw himself on the floor, laughing, with the floor growing a mouth to join in.

Twilight narrowed her eyes.
“Yeah, I do remember that time.”
Then she smirked suddenly.
“And then, Princess Celestia easily outwitted you, simply by sending me my Friendship Reports. It took a lot of foresight and insight to know that that would defeat you in the end. Not just anypony can pull that off!”

Discord angrily stared at her and scrunched his muzzle.
“T-That was just a lucky try! I’m much smarter than she is! There is absolutely NO doubt about that! I’m VERY intelligent!”

Twilight went smug.
“Well, it’s also a common characteristic of stupid creatures to think of themselves as very smart.”

Celestia, while not wanting to be mean to poor pouting Discord, couldn’t help but giggle slightly at the remark. This infuriated the Spirit of Chaos even more.
“OH, HOW FUNNY! HAW HAW HAW!!! You know what is funny to me, Celly? Your weakness! You think that hole impresses me? Don’t make me laugh! I can do that ten times as large! No big deal! But I have an even better idea!”
He snapped his talons and teleported himself and Celestia into the gym’s boxing ring.
Both were wearing a full boxing gear, when they appeared.

Discord lifted his boxing glove covered paw and claw up.
“You may have bested me in a battle of wits, but how about we finally have a direct confrontation? The last time you did something like that was with Chrysalis, as far as I know, and that didn’t turn out so well, did it?”

Something purple pulled itself up to the side of the ring.
“I wouldn’t try that, if I were you, Discord.” Twilight dryly said.

Ignoring the young alicorn, Discord threw a few fake punches in front of Celestia.
“C’mon, Celly! I’ll even let you hit first. Let’s see if you’ll still be laughing when I’m done with you!”

Celestia had a pleading look on her face.
“Discord, please! I don’t want to do this… Aren’t we friends now…?” said the princess unintentionally giving him puppy dog eyes.

“Oh, don’t even try to be Fluttershy! C’mon and fight! Do your best!”

“She’d better do her worst.” Twilight smugly remarked.

Discord leaned towards Celestia and pointed at his outstretched chin.
“Give me some, Celly!”

Celestia looked over at Twilight, unsure what to do.

Twilight smirked, a tiny, devilish glint in her eyes.
“He asked for it, Princess.”

Celestia gulped and turned back to Discord.
“O-O-Okay… if you really want it.”

She slowly lifted her right boxing glove covered hoof and closed her eyes shut.

Two seconds later.

Discord was in the gym’s corner.

…and the ceiling.

…and the walls.

…and all over the training equipment.

“I can’t feel my legs…” groaned what was left of his muzzle.

“We can’t feel you either” one of his legs responded from a distance.

Celestia was grimacing and holding her grumbling belly.
“Oooooooh, Twilight, that was a bad idea!”

Two weeks later.

The door to Celestia’s bathroom opened. The Princess sluggishly came out, head hung low and bags under her eyes.
Twilight was already waiting for her.
“You must admit, Princess, it was worth it!”

Celestia glared at her.
“Maybe for you! Ugh!”

Twilight grabbed her mentor by the hoof and pulled her away.
“No time for discussions! We need to continue your training! There’s a long-needed vacation I want to take and I won’t let some silly threat to the world interfere with it! Or better said: YOU won’t let it interfere with it!”

Celestia silently wailed.
“Ohhhh… has at least Discord recovered? I was feeling so sorry for him.”

“Partially… literally. You know he can pull himself together… even though I hid some parts.”