To my faithful student, Twilight Sparkle,
Twilight, you know you can write to me outside of the context of a lesson, right? I am always pleased to hear from you, and you can ask advice or just catch up any time you like.
As for Birthday Sex... Well, it's not mandatory but it is traditional to celebrate birthdays with pleasurable activity, and more than one pony has given the gift of themselves, if you like. I don't think you need to worry about, say, perhaps Spike for several more years, though I also believe that he is due The Talk at some point in the next year or two. If you do not believe you can handle it, I would be happy to have Spike here and explain the facts of life.
Your loving mentor,
Princess CelestiaPS. If birthday sex was mandatory, would that not mean that I was the one to put it in place? Perhaps I should.