So, I want to write a Princest story. I tried to write one once but the story kind of crumbled on me.
If you have an idea for a story, (CelestiaxLuna or LunaxCadance or CadancexCelestia) please write it.
I'll try to make a story that is at least 10k words long.

4728049 Well. I'm all for Luna x Cadence, but I'm not great at this type of writing. I'm sorry I can't help!

How about a story in which one of sombra's back up plans corrupts Celestia and has her hypnotize and control Luna. Both princesses are Futa. The back up plan would be an unmarked book that hypnotizes and changes the thought processes of the reader, the book would be provided by a crystal pony with the talent for hypnosis, and was commissioned to make the book, and later sombra hides it within the Everfree Castle Library. Celestia would eventually find the unmarked book and read it not knowing how it would entrance her until she finishes reading it and becomes a willing servant to the first pony to find her, however luna would break her focused state but not before she learned how to hypnotize others and was corrupted by the books influence. After hypnotizing luna some time later, Celestia would abuse her power to play with luna's body and eventually have sex with a newly willing luna.

do what you will with this, looking forward to seeing how it turns out in your hands.
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4728130 :/ mind control/hypnosis doesn't sound appealing to me, but thanks for the idea nevertheless.

Hmmm... Cadance walks in on Celestia rutting Luna with a strapon, and they have a sexy threesome.

Oh, and don't forget post-coitus snuggles. Every story needs those.

The Moon Princess wants to practice his speeches, to be as popular as twilight was a returned, and her beloved older sister decides that a section of practice while playing with the little lulu, because according to her could serve the younger to give speeches more natural and more sexy way. of course everything is so great celestia can have fun watching his sister say dirty things and horny in public and as if makes the goddess of night wear a suit or some hottest sex toy with her for these better yet

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Funny, there is a set of pictures like that.

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If you think you can handle it, Cuori Intrecciati could use a sequel....

4728739 Your story is amazing, I really like it, but I would like my own story.

I guess I will try to come up with something for a CadancexLuna, I love uncommon shippings and I haven't seen a story with those two that isn't just a clop fic.

4728690 What a strange and bizarre coincidence. I totally don't have those pictures on my hard drive.

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Me neither, strange indeed.

But yes, to OP, that would be a good idea for a fic, a princest threesome.

4728049

Familiar with butterfly effect? Small change makes things go astray.

This time, Shining Armor`s talent was not guarding, but smithing. He quite prefers forging armor to wearing it. He did not go to the boot camp, but rather have had departed to become a blacksmith`s apprentice in Ponyville. Meanwhile, without his influence, Twilight grew much more asocial and devious, having nothing but petty nobles and spoiled brats to take example from. She still became Celestia`s pupil, but grew up calculating and conniving. This worries Celestia, who saw the same traits in Sunset Shimmer before, and she decides against attempting to set Twilight up to use the elements.
Instead, Celestia puts everything she still can in plan C - Cadence. Cadence is entrusted with the entire knowledge of Elements that Celestia possesses and is sent to Ponyville in order to find the suitable bearers. As she departs for Ponyville, Cadence is followed by Twilight Sparkle, who is in equal parts displeased about being left out of loop and curious about what kind of power could possibly be garnered from the elements. She reintroduces herself to Cadence on the train, and complains about Celestia being aloof and dismissive lately. Cadence attempts to console Twilight by telling her that princess simply has a lot on her mind, inadvertently revealing most of what Celestia explained about Elements.
Twilight offers her help in order to locate the bearers, but she and Cadence start disagreeing on the probable candidates almost as soon as they disembark at the train station. Cadence is less then pleased about practical and somewhat mercenary approach of Twilight`s, who is more or less tallying up everypony they encounter into a spreadsheet in order to run the numbers and see who matches the best. Twilight, in return, is rather irate about Cadence`s "just go and meet ponies" notion, which she dismisses as unreliable. After butting heads for a while, Twilight suggests a solution - each of them would venture out on their own, and attempt to collect the requisite selection of friends "her way". Then, they would meet up after the ceremony and compare the results.
Almost immediately, Cadence runs into Shining Armor. They reacquaint and Cadence tells him about Twilight being in town as well. Obviously, he wants to meet his sister immediately, but Twilight is nowhere to be found. Meanwhile, Twilight methodically scours the town in search for ponies responsible for Summer Sun Celebration, using the information she collected in Canterlot unbeknown to Celestia. Her logic is simple - ponies hoofpicked by Celestia should have something to do with this whole Elements business. She is working from incomplete information, however, and is not aware Celestia already admitted to Cadence she has no idea who could possibly use the elements successfully. Twilight is assuming that Celestia have had managed to assemble almost entire set of bearers already, and intends to fill up the remaining position before Cadence does. She surmises that Cadence have had insisted on "just meeting ponies" as a diversionary tactic, being already fully aware who the bearers are.
Twilight meets up with each of the original Mane 6 and secures a promise from each to meet up during the ceremony. Twilight presents herself as a representative of Celestia as she does, using this pretense to make Mane 6 think she is there to supervise them and dole out some manner of reward if the ceremony goes as planned. She makes an effort to avoid being seen by Cadence as she does so, being certain Cadence would interfere in her plan to snag an element for herself.
Meanwhile, Cadence and Shining Armor keep looking for Twilight in Ponyville, meeting various ponies as they go. While at this, they lose track of time, and end up attending the ceremony in a hurry, arriving there just in time to see Nightmare Moon making a touchdown. Twilight have had already gathered up her team and left quietly, telling them that they lack wherewithall to deal with Nightmare on their own, and that their only hope is hidden in the ruined castle in the Everfree. Unaware of this all, Cadence is beset by a number of ponies demanding a guidance from princess - any princess. She asks for volunteers to go with her to the Everfree forest to "save Celestia". Shining Armor volunteers immediately. He is joined by Big Macintosh and Bon-Bon quickly. Due to Bon-Bon volunteering, Lyra throws in her proverbial hat as well. Rounding up the selection, Derpy blunders into Cadence and volunteers accidentally, as she tries to apologize.
Cadence orders the rest of Ponyville to hunker down and wait, and departs for the castle with her own team. She is not aware Twilight has a headstart, and neither is Nightmare Moon. As such, Twilight still encounters a few of the trials as in the canon, such as trusting Applejack and allowing Fluttershy to calm a manticore, but neither haunted trees nor Steven Magnet bar their way. River still blocks the way, however. Tempers rize as they fail to find a decent way across the river, but Pinkie Pie shows her aptitude for laughter by defusing situation with some well-placed jokes, poking fun at how ridiculous her friends are when they yell at each other. Twilight gets an idea to fashion a raft to get across the river, and things almost go well... except for the last moment, when an awkward step pushes the raft away while Pinkie Pie and Applejack are still on it. Dash shows her loyalty as she gets both of them off the raft before it floats away, claiming that "nopony is being left behind on my watch". Finally, Rarity shows her generosity by using some of her mane and tail to fashion a rope to fix the fallen bridge with, when they arrive to the castle. Behind them, unaware Nightmare Moon sets up the obstacles.
Cadence`s team goes about things a little differently. Big Mac gets generosity as he placates a bear woken up by all the clamor with a barrel of apples. Nightmare Moon manages to enchant the trees by now, but anytime a tree tries to menace somepony, it`s bumped into by Derpy, and thus rendered too ridiculous to fear, thus earning Derpy an element of laughter. Steven is calmed down by Lyra`s song and melody, thus getting her an element of kindness. Nightmare Moon attempts to sabotage the team by subverting one of the members, but only ends up helping Bon-bon earn loyalty. Finally, Nightmare Moon`s mien itself is shaken when she attempts to turn away the team personally, citing all the "injustices" against her by Celestia, and ends up on receiving end of Shining Armor`s honesty, who explains that he knows what`s it is like to be overshadowed by your own sibling, but lashing out is never an answer.
Enraged, Nightmare Moon teleports to the elements... Which are already removed from their resting place by Twilight. Unaware of sixth element having had to appear when the five are known, Twilight makes a mistake of assuming Nightmare Moon have had kept the sixth artifact on her. Since she believes that artifacts are magic weapons, she hastens to jury-rig the solution. Using a spell to idenfify which of the stones has best affinity for which of her companions, she hands them out, explains her plan to use herself as a magic conduit to beat the last element out of Nightmare Moon with the help of five she has... and admits to trusting them when Mane 6 express their doubt and worry about possibly hurting Twilight.
Everyone intersects in the hall of elements. Enraged Nightmare Moon is immediately beset upon by Cadence and her team, and each accuses the other of stealing the elements. In an awkward moment that happens, Twilight delivers her strike. It is, strangely enough, successful, and Twilght gains the element of Magic, but recoil renders all of them unconscious while the harmony strike splits Luna and Nightmare physically. First is out for the count, and Nightmare attempts to run, but is contained by Cadence - barely. During a magical struggle that follows, Cadence asks her team to carry away the unconsious Mane 6 and Luna before Nightmare breaks free and possesses one of them. As Cadence`s bearers each grab the pony with their respective element, Magic suddenly winks over to Cadence and gives her a magic boost, allowing her to eradicate Nightmare entirely with a harmony-powered love blast... Which concurrently hits Luna.
Celestia arrives finally, to see two full sets of potential bearers and a sister lovesick about her niece. Cue facehoof.
Feeling responsible, Cadence insists on taking care of Luna. First out of guilt, then out of interest, and finally out of affection. Meanwhile, Celestia faces the problem of patching things up with Twilight - whom on one hoof is feeling betrayed, on other - is already vindicated. Twilight is reasonably bitter about things, but ultimately, agrees to let the bygones be bygones, on condition that Celestia allows her to live "anywhere but Canterlot", which Twilight hates with passion. Things remain tremulous between the two for time being.

4729580 This sounds interesting but I pass. As I told TheLandgrave, I want my own story. This one is practically complete, it would only need to add the details here and there.

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Well, you asked. if you just want bare bones concept, here`s some.

1) How`d Cadence cope with the fact her husband is mortal? (Obviously needs to be set well in future, current Shining Armor is quite hale as of the moment.)

2) Cadence`s origin. The popular rumor is that she`s a result of one of Celestia`s little indiscretions, but what exactly did Celestia do? (Works on a misunderstanding - Cadence isn`t a daughter, but rather an accidentally ascended lover.)

3) Nightmare Moon was caused not by ponies being dismissive towards Luna, but rather by the lapse of relationship between Luna and Celestia. Now that Luna is back, they both agreed the relationship have had been gone for millenia... but now Celestia wants to reconnect, even if she`s loathe to admit it.

4) Cadence and Luna end up bumping heads in their divine duties far more often then one would think - a lot of love affairs is settled at night, after all. Cue "work romance".

5) Sick with flu, Cadence can`t properly control her powers and gives off an uncontrollable love aura, making it explicitly hazardous for anypony save princesses to approach. But are even alicorns resistant to this aura enough?

___

There, ought to be enough to jostle the old imagination.

no clop: Luna help Cadance adjust to society the Crystal Empire
clop: Princess of the Night and the Princess of Love, decide who will add "Princess of Sex" to their titles

Luna and Celestia. Deep romance, non-clop, something beautiful and very emotional.