This is an idea that wouldn't leave my head, inspired by Fairy Slayer's "Mommy Nearest," Aldea Donder's "Alicorn," SoundofRainfall's "Play" and RainbowDoubleDash's "Lunaverse"

Alternate Universe: Instead of Twilight Sparkle, Princess Celestia made Rainbow Dash her personal student instead! Follow her through the events of the 1,000th Summer Sun Celebration. A reimagining of "Friendship is Magic"