Derpy the mail mare delivers a special present for Twilight from Rarity - with such a strange shape, surely it's a horn warmer? She decides to try it on, and go thank her friend for such a generous gift.

Hilarity, as they say, ensues.

NOTE: This is actually rather tame with no real explicit content, but since the theme is rather adult, I've labelled it as teen. it's not what I would call worthy of being mature, but... the little ones probably shouldn't read it. YOU HAVE BEEN WARNED.