Princess Celestia and the summer of royal waves

the long version

"With a class of students about to graduate, the Summer Sun Celebration just around the corner, and a brand-new princess of friendship in her realm, Princess Celestia is more than just a little overwhelmed. Her sister, Luna, suggests she enlist a guest professor to help out during the last few weeks of the academic year, and Duchess Diamond Waves from the land of Monacolt is more than happy to help. Things look great at first, but Celestia soon notices that the duchess doesn't seem to be teaching at all. Instead, she's encouraging the students to relax and have fun. It's a completely different approach than the focused, studious methods Celestia uses. Just what does the duchess think she's doing? Celestia is not pleased. She was supposed to get help! Not more trouble!"--