You happily sigh as you lean back onto your swimming tube. Your eyes are closed and your sunglasses are on. The water beneath you is cool to the touch, which makes it quite comfortable on this extremely hot summer day. The gently flowing current in the water carries your tube slowly forward, and it feels as though your troubles are miles away.
"Sunshine?"
"Yes, Tia?"
"I, uh... I could use some help."
You lift your sunglasses, open your eyes a bit, and tilt your head towards Celestia, your retired alicorn wife. Her large alicorn wings seem to be giving her trouble, making it difficult for her to get comfortable in her tube. In fact, her rear end appears to have gotten stuck in the center of the tube while her wings are awkwardly stuck on the outside of the tube, lazily following behind her in the water. Meanwhile, even though she has her mane tied back in a ponytail, it's still so long that it dips into the water. All in all, she doesn't look like she's having the best time.
With a chuckle, you carefully maneuver yourself in her direction as you both slowly float down the lazy river. Today was a vacation day for the both of you, and you chose to spend it at a water park near Las Pegasus. You had a great time enjoying the many attractions, slides, and rides the park has. Specifically, Tia did, thrill-seeker that she is. While you didn't have a bad time or anything, something slower and more relaxing is more akin to your tastes. Thus, at the end of your long, tiring day, you suggested that the two of you take some time to rest in the lazy river. Celestia, having already experienced everything she wanted to in the park, agreed.
At this time of day, the sun is already starting to set. As such, the park is quickly clearing out. In fact, the two of you are somehow the only ones on the lazy river at all. It's almost a bit jarring, but you don't care. It just means more peace and quiet for you and your wife.
"There you go."
You finally finish getting Tia unstuck from her tube. Well, sort of. She, uh, has an... "above-average-sized" flank, and it's going to be a bit difficult for her to get out of that thing no matter what. But hey, at least she's comfortable now.
"Thank you, sunshine. Now, uh... how long is this river?"
"Well it's a loop, so it depends on your definition of long. Until we get out ourselves, we'll just keep on floating."
"And how long do we plan to float?"
"If you're getting bored you just let me know. Until then, I'm unbothered. Moisturized. Happy. In my lane. Focused. Flourishing."
"Sunshine, what the hay are you talking about?"
"I'm vibing, Tia."
"I don't understand the words coming out of your mouth."
"Straight chillin'."
"'Chillin'?'"
"I'm floatmaxxing over here."
"I'm fairly certain that isn't a real word."
"I am relaxing, dear."
"Okay, I understood that one."
You chuckle as you place your sunglasses back over your eyes once more. This is the life.
"Oh, sunshine, would you look at that? A waterfall."
"Hm? Oh, yeah."
You open your eyes and glance up. This part of the river goes underneath a sort of cave-like overhang. A few gentle waterfalls come from the ceiling near the edges of the river, adding a great deal of ambience to the space. You're heading right towards one, but you make no effort to move.
"Hmhm, you're going to get wet, sunshine~!"
"Meh. That's fine by me. If that's what the lazy river gods have decided, then that is how it shall be." You close your eyes again. "I welcome the wetness."
You don't even bother tensing up as you hear the water coming your way. The sounds of water hitting water and your wife giggling fill the space, and the next thing you know, a gentle stream of water is pouring over you. You simply smile and let it happen, waiting for your tube to bounce off of the wall and move you away from the waterfall. Sure enough, the water stops hitting you. And yet, something feels... off.
You're pretty sure you didn't hit a wall.
From a distance, you hear your wife's voice.
"Anon? Where did you go?"
You open your eyes once more to look around. To your surprise, you appear to be inside a building. A long hallway stretches out in front of you, the walls and ceiling made up of dated-looking tiles. Very old lights that gently buzz are embedded into the ceiling, and the whole place smells strongly of chlorine. You glance behind you, noticing that the same waterfall you just went under seems to be pouring down into the river from a slit in the ceiling. However, you can clearly see a solid wall behind it. How did you pass through that? There is no door or anything, just the end of a hallway with a floor made out of lazy river.
Your eyes widen slightly as you see Tia suddenly pass right through the wall, a look of complete shock on her face.
"Anon? What is this place?"
"I have no idea. Did we go through that wall?"
Forgoing typical lazy river etiquette, Celestia starts kicking her legs in an effort to swim over to the waterfall. She presses her hooves against the wall behind it, only to find that she does not go through.
"It's solid now!"
"Huh. Weird." You shrug as you lower your sunglasses once more and lean back onto your tube.
"Wh-why are you acting so calm about this?!"
"I do as the lazy river guides. If the river wants to take me this way, then this way I shall go."
"Nonny. Honey. We just passed through a solid wall. I feel like that should be a cause for concern."
"If you want to break out then break out, I'm not stoppin' ya."
Tia lets out a huff before her horn starts to glow. However, the glowing quickly fades as the magic peters out.
"What?" She tries again, and the result is the same. "M-my magic isn't working!"
"Peculiar," you say in a completely calm manner.
"Anon, can you please take this seriously?! We could be in real danger!"
"How?"
"What do you mean, how?!"
"Look around us, Tia." You motion to the hallway around you and the river that stretches very far in a straight line before making a sharp left turn. "Do you see anything that could harm us?"
"W-well, no, but that doesn't mean-"
"Chill, Tia. Take a deep breath."
With an annoyed look on her face, Celestia does as you say and takes a deep breath, doing her best to collect her thoughts. After doing so, she paddles back up to you before hooking a wing onto your tube, essentially locking your tubes together.
"Fine. We'll do it your way. But I'm not letting go of your tube until we get out of here."
"That's fine by me."
With a smile, you reach a free hand over to your wife and scritch the back of her neck, causing her to let out a tiny coo.
"Not now, sunshine."
"Alright, alright."
Thus, the two of you continue to slowly float down this strange, liminal space you've found yourselves in.
"Hey, check that out!"
"Hm?"
You lower your sunglasses and open your eyes as your wife tries to get your attention. You are now in a much wider corridor than before. The floor is still entirely made up of water, but along one wall, you can see where a slide appears to enter this room from another floor before twisting around at angles that wouldn't be comfortable to slide down and eventually ending beneath the water. All in all, it looks like a very nonfunctional slide.
"This place is creepy."
"I dunno, I think it's kind of cozy."
"How is any of this cozy?"
You shrug.
"Tia, we've had to fight villains to save the world on numerous occasions. We live next to a country full of dragons. You can move the sun. Excuse me for thinking that the weird lazy river rooms are a nice change of pace."
Tia lets out an aggravated sigh.
"You're impossible sometimes, you know that?"
"You're literally thousands of years old, Tia. Shouldn't you be the jaded one here?"
"Bite me."
"Don't tempt me."
"Sh-shut up!"
"Haha!"
"This just keeps getting weirder."
Tia speaks up once more, causing you to yet again lower your sunglasses and look at the room around you. This room is massive, bigger than most buildings. You see all sorts of towers leading to slides, children's playthings, chairs for lounging by the pool, and what looks to be a deep end to the water on the opposite side of the room. However, the current beneath you is gently taking you in a straight line along the back wall of this room, which will ultimately send you into yet another adjoined corridor.
"Huh. It's an entire indoor water park."
"B-but we just came here from a different water park."
"Neat. You get more bang for your buck this way."
"Are you suggesting we get out of our tubes and explore? Because somehow, I think I want to do that even less than what we're already doing."
"Nah, I'm too comfortable to get up."
"That's your reason?"
"Seems like a sensible reason to me."
"Ugh."
You are caught off guard by your tube bumping into something. Looking ahead, you see even more tubes in the water before you. They come in all shapes, sizes, and colors, but none look like the ones you and Celestia are in. After all, the tubes you two are in have branding identifying the park that they came from. These other tubes have no such branding.
"Where did all of these tubes come from?"
"Oftentimes water parks will keep tubes in the water to make it easier for folks to just hop in and go. Plus, it keeps them cool."
"But these tubes aren't from our water park, sunshine."
"And? We passed a completely different water park just a bit ago. Maybe they're from that one."
"But there was nopony there!"
"And there is nopony in these tubes, either. Seems logical to me."
"Well not to me! Seriously, what is going on?! Anon, I want to go home!"
"You're starting to sound like a whiny child, dear."
"This isn't the time for playful banter!"
"What's the rush?"
"What do you mean, 'what's the rush?!' This is super weird!"
"And what do you propose we do? We can't go backwards, there's a solid wall all the way back there. The only way to go is forward, and we don't know how far this river goes. So, if you feel like risking it and swimming the rest of the way, be my guest. But I'm gonna stick to my tube."
"...I hate that you're right."
"When am I wrong?"
"Often."
"You know you could have at least hesitated when you said that."
The hallway is suddenly intersected by many other hallways, their floors also made of water. As you and Tia continue to float in a straight line, the empty tubes that have been floating in front of you all get funneled left and right down these other hallways. The buzzing coming from the lights in this hallway's ceiling feels louder than it was before, too.
"I wonder where those go."
"Wanna find out?"
"Unless one of them leads to an exit... no, not really."
"Thought so."
"What if the current sends us down one of them?"
"Then we should-"
"Do as the lazy river guides?"
"Now you're catching on."
You give her a wink. She huffs. It's adorable.
"Fine."
There are no longer any other tubes in your hallway. The two of you gently float without saying much for what feels like an hour or two, the only sound being the buzzing lights on the ceiling. Suddenly, you hear what sounds like running water, causing you to look ahead once more.
"Uhh, Anon?"
"Yeah?"
"What's that?"
You tilt your head forward just a bit to get a clearer view at what's in front of you. About a hundred feet ahead of you, the hallway seems to come to a sudden stop. However, in its place, you can see the plastic yellow outline of what looks to be the entrance to a massive water slide. It's easily big enough to fit both of you while you're still in your tubes, and it appears to be the only way forward.
"A slide."
"And... we're going to go down it?"
"Do you see any other path we can take?"
"Enough with the sass, Anon. We don't know where that slide goes, it could... ugh. I don't even know why I'm bothering to say any of this anymore."
Celestia groans as she leans her head back in frustration. You glace at her before letting out a deep sigh. Removing your sunglasses entirely, you reach over and grab your wife by the hoof. She looks up at you curiously.
"Alright, alright. I'll start taking this seriously. I can tell it's starting to get to you."
She glances down at her hoof as you give it a gentle squeeze.
"...I just don't want anything to happen to you, sunshine."
You chuckle. You had a feeling it was something like that.
"Of course you were more concerned about me than yourself. That's just like you, Tia." She gives you a mocking smile and glances away. "...Thank you. Whatever comes next, we'll face it together, alright?"
"...I know you're trying to cheer me up, but let me just say this." You both glance forward. You'll be going down that slide in just a couple of seconds whether you like it or not. "If we die, I get to say I told you so."
"Yeah, that's fair."
Those are the last words spoken before the two of you disappear down the slide, your tubes going ever faster as the mysterious slide takes you down farther and farther.
You both gasp as you're suddenly hit by a gentle stream of water from above. Your eyes need to adjust as you exit the slide into a much brighter setting. The two of you get a grasp of where you are, and you both let out a laugh of disbelief.
"See? I told you, Tia!"
"I so, so hate it when you're right, but right now specifically, I just want to kiss you."
She does, in fact, lean over to give you an excited smooch on the cheek. Behind you is the gently flowing waterfall in front of a solid wall, and in front of you is the familiar sight of the lazy river at the water park you spent the whole day at. To your surprise, the sun still hasn't finished setting, even though you're fairly certain you were in that strange place for a good number of hours.
"All's well that ends well, I guess."
You let out a contented sigh as you both reach the exit point. You squirm out of your tube and deposit it back into the water. Meanwhile, Tia cannot get her flank out of her tube on her own. After you give the now red-faced mare some assistance, you're both free and back on dry land once more.
"Should we tell park staff about that, or...?"
"Meh. Not our problem anymore."
"But what if... you know what? Screw it. I'd rather just forget any of that happened."
"Want to go get dinner?"
"Only if you're paying. Water park prices suck."
Thus, your strange journey through... whatever that was comes to an end. While your wife will likely have a much harder time forgetting your adventure than she claims, it didn't seem all that special to you.
After all, you're married to an immortal pony that used to be a princess. It doesn't get much weirder than that.
And you wouldn't have it any other way.