Dear Princess Celestia,
I hope things are going well with you. As for myself, things have been quite crazy these past months, but I have long learned to accept things for what they are. Being a father is a challenge I never expected to have so soon in my life, but everyone has been very supportive and I love my little ones. That being said, I would like to keep some degree of my prowess a secret. I know you and Luna are good at keeping secrets, but I am concerned Cadance might suggest renting me out again.
Spike

"That should be good enough." Spike said to himself, just blowing his flames on his scroll. "Now I can finally relax."

Laying back in his bed, he pondered how this all happened. Well, he knew how it all happened, but was more wondering how he came to accept all this. After getting his revenge fuck in on the Princesses, he went straight home to establish his own dominance over his friends. Whether he was blinded by his anger, or perhaps something primal in his dragon brain finally clicked, but he showed the mares that he was their new master and they were his loyal harem. Not that they complained, they were eager to take his hot loads and before he knew it, they had all gotten pregnant. Twilight had a boy, Rarity a girl, Applejack a boy, Rainbow Dash two girls, Fluttershy a boy and a girl, but Pinkie Pie ended up having the most at three boys and two girls. When his frustrations and boner finally calmed, and he realized what he did, Spike was naturally very concerned, but when the girls reassured him he'd be a good father, he eventually accepted; embracing his new role as parent.

This didn't stop their little escapades, not by a long shot. Even while pregnant, the girls were insatiable. Spike couldn't think of a single night in the past year that he didn't have his dick in one mare or another. Even the Princesses were not spared from their deep carnal cravings. Celestia was the most eager, constantly calling Spike over to give her royal pussy a brutal fucking, even while she herself was pregnant. Luna was a little more refined, settling on simple foreplay and cuddling throughout her own. But Cadance had the weirdest fetishes, even if Spike refused to fuck her pussy near the end of her pregnancy, she had him fuck her throat or ass with the same degree of passion. Part of the dragon believed this may have also carried to their children. Celestia has a little girl, Luna had a quiet boy, but Cadance had a needy daddy's girl that hated being pulled away when she hugged him for too long.

"Alright, I believe I earned a little nap." Spike said to himself, looking over to see a figure was sleeping in his bed. Sighing, he pulled at the blanket to see who it was. Mentally, he was making bets on who it was. But as he pulled it away, he saw it wasn't any of the girls, it was in fact Trixie. She lay on her side, her soft ass facing Spike as the clear indication of his deed leaking out of her pussy. Before, Spike would've freaked out, but at this point, he shrugged his shoulders. "Was bound to happen eventually."

Getting up, not to wake the mare, he resigned himself to take a nap in another room. Walking through the halls, he could see that the girls were over, as he could hear the faint echoes of the foals' crying and giggling. They were a rambunctious bunch, but deep down, he loved them. Deciding to pay them a visit, he walked in to see a very exhausted Starlight Glimmer. Though he tried to sneak away from this, his attempts did not escape the mare's attention, who was quick to drag him back by the strength of her magic. Against such a force, Spike was powerless, so he accepted his fate.

"Do you have any idea what I have to put up with foalsitting?" Starlight asked, stomping over to the dragon, poking his chest. As she approached, he could see a faint blush on her face. Leaning in, she whispered. "Don't think just cause Trixie got out of sitting by getting you to fuck her slutty ass into a sex coma doesn't mean I'm not gonna have my share when she wakes up."

"I-I see." Spike nodded, processing what was happening, or rather what was going to happen. "I'll keep that in mind." Before Starlight could get a chance to reply, be made his escape. Alone with his thoughts, he pondered. 'Alright, so that's those two now added to the list. I wonder who else.'

His answer came in the form of a large group gathering in the Cutie Mark Map Room. Not only were his friends there, but he could see the Cutie Mark Crusaders, Smolder, Ocellus, Yona, Silverstream, Zecora, Mrs. Cake, and even some mare's he's pretty sure he hasn't fully met. At this point, he assumed every female in Equestria and the neighboring kingdoms wanted his dick. His sigh of annoyance was only interrupted by the burping green flames of a scroll, baring Cadance's insignia.

Dearest Spike,
Words cannot express how overjoyed I am that you have been spreading the passions of love throughout Equestria. It brings me nothing short of pure bliss that your magnificent dragon cock can bring such a euphoria, I can't go an night without finger the same sobbing wet cunt you so savagely fucked open so long ago. I cannot wait to see you!
Your Slutty Princess
Cadance

"Well shit." Spike said to himself, looking at the letter, then at the crowd, then back to the letter, then to the crowd. SIghing, he knew Cadance not only must've spread word but must've also handed out invitations that he was some breeding stock. "I'm gonna need a drink."

Author's Note

I didn't know if this series needed a conclusion like this, but I am happy with its result and hope you all enjoyed it as well.
If you believe I should revamp the series into something a little bigger, please comment down below.
Thank you, and enjoy!