Delightful, but the punctuation needs a little work. You seem to be (like me) coming from a British English background, and are confusing it and US English together.

“And,” Starlight added, “this could prove to be an historical event of great significance”.

If you are using British English, you should be using single-quotes, commas and periods outside of quotes:

'And', Starlight added, 'this could prove to be an historical event of great significance'.

For US English:

“And,” Starlight added, “this could prove to be an historical event of great significance."

Apart from that, the only serious error I found was:

“Hello, darling” Rarity cooed.

Missing the comma after "darling"

I eagerly look forward to what will be coming from your keyboard next, bravo.

Meanwhile at the bathroom where Rainbow and Fluttershy are taking their time......

Now dance for a different prince.

He's going to bite himself in the butt for scaring you off. Unless he starts nibbling on yours.

Bronyb3n made the picture, right?

I loved it. I loved all of it. This was truly a fantastic story, and I love how the shipping at the end was only implied.

This story was so great that I'm putting it in my special folder. It took me THERE...

7940980 No, that's one of mine.

The young princess wondered just how debauched the elite of Equestria actually were, behind closed doors.

I promise you: There are some things you better don't know. Yet.

Nice story.
Well done.
I'm just wondering why Spike didn't want to come along...

7940614 I've fixed that error, thanks for pointing that out.

With regards to the different styles/rules, are there any resources you could point me to so that I could research this myself? To be honest if we're getting into an area where there are many different standards and a lack of consensus, I'm not too worried about following one set of arbitrary rules over another. Maybe if I could read some of the arguments for/against a particular style, I'd change my mind.

7942777 I imagine the girls didn't tell him what was going on.

7942820
: "And here everyone is wondering why I always feel "left out"... I mean, I had been the ruler of dragonkind! (For a short time.)"

No, it was probably better he stayed home and read his comics.

7942818 If you are just after the US rules for punctuation, I highly recommend Grammar Book. But for the differences in rules between US and British standards, see The Punctuation Guide.

There is nothing inherently wrong with the British style, it is the standard here in Australia after all, but I have found that for a mainly international audience, the US punctuation/grammar styles are the best.

and we sort of… convinced Pinkie Pie that it wasn't really her sort of thing, either. It, uh, didn't seem like a good idea to bring her along.

That seems ... eminently sensible.

Starlight's expression of polite interest was honestly a little unnerving

a little?

“They've both been in their a while, now”.

*there

7951725 Fixed the typo, thanks.

Well, this was a nice ending. If only I could upvote more than once.

Can you please write a spin off story about Dash and Flutters in that bathroom?

I really like this fic. It's SO hot!!!! I just have one question about it though. Where the fuck is Sweetie Belle!? Doesn't she also live in Carousel Boutique? How did she never notice Rarity wearing that chastity belt? Why didn't she hear the loud bell noise when Rarity tried to remove the butt plug? WHERE WAS SHE???

8366649
First of all, thanks. Feedback is always welcome, especially compliments .

I'm afraid I've no plans to write a spin-off, though.

As for Sweetie Belle, my understanding is that she doesn't actually live at the Carousel Boutique with Rarity most of the time — she lives with their parents. She does sometimes stay with Rarity ­— in the Sisterhooves Social episode, their parents are off on vacation for a week and leave Sweetie Belle with Rarity — but I'm not sure how often that actually happens.

So… yeah, she's not staying with Rarity during this story.

7942777
Eyes Wide Shut

9121032
Thanks, I'm glad you liked it.

The story flow is surprisingly good.

10782932
Thank you

This was. This was hot. I don't know how else to say it but the manner in which they're all treating this "show" is so strange yet enticing.

This was a great read