It was Sunday and Spike’s day off.
He’d just eaten breakfast with Twilight and was now lazing in his basket, flipping through last week’s issue of Playcolt without much interest. He’d already read everything that was worth reading and looked at all the pictures that were worth looking at many times before, and now he was bored. He heard the sound of hoofsteps coming up the stairs, and quickly hid the magazine under his basket just as Twilight’s horn became visible over the top of the stairs.

He got out of his basket and made for the stairs, shouting as he went along “Hey, Twilight, I’m going out for a bit.”.

“Where to?” she inquired.

He thought about it for a moment - he hadn’t really thought that far - before replying “I dunno. Maybe I’ll go see if Rarity needs help with anything.”.

“Okay. See you later then!” Twilight giggled as he disappeared down the stairs.

The walk to Carousel Boutique was uneventful, as was to be expected on a Sunday.
Spike knocked on the door and waited a while, but nothing happened. He knocked again.
Still no response. Was Rarity out? He tried the handle, and the door opened.

“Rarity? Are you there?” he called out.

There was no response, but he thought he could hear a low noise coming from somewhere inside. He ventured further into the house. There was no doubt now - he could hear the sound of running water coming from behind a door in the hall. Was Rarity in the shower? The mere thought of this made him blush. He contemplated leaving to come back later, but the temptation to sneak a peek made him hesitate.

“This is WRONG. I shouldn’t do this!” he told himself, “It’s a bad idea! Rarity will find out and get mad!”. “...but this is a chance you don’t get everyday!” his inner dialogue chimed in. “You may never get the chance again!” it continued.

He suddenly realized he was hunched on the floor, pulling at his scales, while his inner dialogue argued with itself.

“Shut up!” he thought, and the voices died down.
He decided to take a look inside. After all, this WAS a once in a lifetime opportunity. He gently pushed at the door, and it opened slightly. The flowery smell of shampoo emanated from the crack in the door, and steam poured against his face as he put his eye up to the opening.

Nothing could have prepared him for what he saw. Rarity was indeed in there, and she was softly humming the tune of “Art of the dress” as she stood under the shower, rinsing out the shampoo and enjoying the warm water trickling down her body.
Her normally well-groomed and styled mane and tail hung limply straight down, weighed down by the water, and a lock of her beautiful purple hair fell down between her closed eyes.
The very sight of this made him instantly grow a raging boner.

At this point his vision had gone all pink and glittery, and he was completely oblivious to his surroundings when a sweet voice sounded from behind him.

“Hi, Spike!”.

He almost jumped in surprise, and quickly grabbed a vase that had been standing next to the door to hide his boner as he turned around to see Sweetie Belle smiling innocently at him.

“What are you doing here?” she asked, “Did you come to see Rarity?” she continued without waiting for a reply. “She’s in the shower you know. She’ll be out any minute I’m sure.” she went on. “Would you like some juice?”.

Spike shook his head.

“Why are you holding that vase?” inquired Sweetie Belle.

Spike wasn’t quite sure what to say to this, so he just grinned sheepishly and hoped she would move on to another subject or go away. Unfortunately, she didn’t, and as she tried to peek around the vase, he was forced to move it around to hide his still massive erection.

Suddenly he was startled by the sound of the door opening behind him.
Rarity had apparently finished taking a shower and was coming out.
The shock made him drop the vase, causing it to fall to the floor and shatter.

“Ooooh, what’s that?” asked Sweetie Belle in fascination, her large round eyes now firmly fixed on his humongous cock.

He didn’t answer, but instead turned and ran towards the exit, only briefly turning his head around to see Rarity standing next to Sweetie Belle, staring at him with an expression of mixed anger and surprise.

He ran for what felt like hours, even though it was probably only a few minutes, before slowing down and wandering aimlessly around the outskirts of Ponyville, where he was unlikely to encounter anypony else. He had never in his life felt so ashamed before. Now Rarity would surely hate his guts for all eternity, and even if she didn’t, how could he possibly face her after this. He lay down on the ground, staring up at the sky, and wept at the thought of never being able to face Rarity again, before slowly dozing off into an uneasy sleep.

The sound of hoof-beats in the distance woke him up. He wasn’t sure how long he’d been sleeping, but he guessed at least a few hours. Still lying on his back, he looked around to see who was coming, but couldn’t see anypony before a friendly pink pony with a poofy pink mane poked her smiling face into his field of vision from somewhere behind him.

“Hi, Spike!” she said cheerfully.

“Pinkie Pie? What are you doing out here?” he said.

“Oh, silly, I was about to ask you the same!” she exclaimed happily.

Spike didn’t feel like discussing his unfortunate situation with anypony right now - especially Pinkie Pie. “Just, you know... taking a nap.” he said in as manly a way as he could, realizing perfectly well how lame it sounded, and almost facepalming himself. Pinkie Pie, however, didn’t seem to have noticed.

“Oh, that’s right!” she said, “I came to give you this!”, and produced a pink piece of cardboard seemingly out of thin air.

“Where did...” he began, then cut himself off in mid-sentence. He knew better than to question the mysteries of Pinkie Pie. Some things were probably best left unknown. He took the pink object from her muzzle and examined it.

Before he could read it, Pinkie Pie went on “It’s an invitation to a party!”.

“What’s the occasion?” Spike inquired, raising an eyebrow.

“Oh, silly, since when did I need an excuse to throw a party?” she laughed dismissively.

He had to admit, she had a point.

“It’s at Sugarcube Corner at 8pm! Be there, or be elsewhere!” she shouted cheerfully, before bouncing happily away from Spike and vanishing in the distance.