The next day, Spike asked Rarity to give him some lessons on manners and poise and such.
"I want to learn how to act like a prince early so that I don't have to waste time taking lessons when it's time for me to assume the throne." Spike explained.
"Why I'd be more than happy to teach you." Rarity smiled; then she froze.
"Is something wrong?" Spike asked.
"No, I just realized that for the longest time I had dreamed of marrying a unicorn prince, now it turns out that I have ended up with a dragon prince." Rarity said, sounding amused at having just realized this fact. "Looks like I got the title right but the species wrong." She giggled.
"I didn't think of that until now either." He said.
And so, Rarity started to teach him manners. She started off with table manners, since he obviously was a total kid when it came to eating. Spike, to please Rarity, learned quickly and also learned to not find having manners boring or tedious. Rarity then started moving up with the lessons, first starting with the basics and then adding a few things everyone should know when entering a palace. She didn't know everything on her own, so she later checked out a book on royal manners to help her. She also started to practice the royal manners herself, as she had a feeling that she would be a frequent visitor to Drakeria along with Spike.
And she was right. She visited Drakeria almost everytime Spike did. They and their friends were pleased to find that Drakeria had recovered from the rogue dragon attack quickly and was going back to thriving. Time passed, and Spike and Rarity grew. Rarity didn't grow that much more, due to not being an omnipotent unicorn like Celestia or Luna, just a little over another foot. Spike grew to be as large as his parents - just a couple feet larger than Celestia - but didn't let the difference in size affect his relationship with Rarity. Many years later the time had come for Spike to assume the throne, and when that time came he proposed to Rarity. She accepted, and their wedding was grander than the one she had daydreamed about with Blueblood as the groom.
Both she and Spike proved to be among the best rulers Drakeria ever had. Rarity was first famous in Drakeria as Spike's girlfriend, and then famous for being a wonderful queen. Both of them missed living in Ponyville, but grew to love their new home in Drakeria. Despite being a queen Rarity did not stop making dresses and other outfits for ponies, in fact she even expanded into making outfits for dragons as well. Since she couldn't deliver her packages herself anymore, Spike hired some dragons who were fast yet careful flyers to do the job for her. Her designs became more famous in Drakeria than they ever had in Equestria.
Not too much later, Spike and Rarity had a son. He was at first an ordinary looking pony, though interestingly did not have a horn due to being part dragon. He had Spike's body coloring and eye color and Rarity's mane coloring, with his mane resembling Spike's head spikes. They named him Amethyst. Since unicorns, despite having similar lifespans to tame dragons' lifespans, mature faster, Amethyst too matured a little faster than dragons would, so he got a very dragon feature early: reptilian wings. This made him the most unique creature ever, but he never let that go to his head. He always considered himself equal to the other dragons and ponies, and was especially fond of his Aunt Twilight.
Twilight enjoyed her new role as a princess, even though she rarely did any princess duties like Celestia or Luna. She also loved creating new color patterns for the hour of twilight every day, and sometimes came up with special patterns for special occasions. Despite being crowned a princess, she rarely wore her tiara. In fact pretty much the only times she wore her tiara was during the future Grand Galloping Galas, which were a lot better than past ones due to Celestia having both Luna and Twilight as helpers. Twilight also hardly lived at the palace, but the first time she did she enjoyed her new bedroom as it resembled an observatory/planetarium. She always remained close to Celestia, but also grew closer to Luna until it was like the two had always known each other.
The others also had happy futures, and continued to visit each other despite sometimes being very busy. Applejack and Big Macintosh took over Sweet Apple Acres together, Pinkie Pie took over the Sugarcube Corner, Fluttershy continued her duties with the animals but also continued her spa outings with Rarity (they just had them less often), and Rainbow Dash, yes, Rainbow Dash finally got into the Wonderbolts.
Oh, and the lesson on friendship Twilight learned from their journey to Drakeria? Well, she learned, thanks to Spike, that if you help your friends and act from your heart you don't get what you want...instead, you get something better.