-by Katase Minami
-17 pages, English translated
Due to a misunderstanding Shokuhou Misaki thinks that Touma is the boyfriend of the Ace of Tokiwadai (Mikoto). Well I guess to understand the full ecchi story you would have to read toaru majutsu no index and toaru kagaku no railgun. However, even without knowing these anime/manga you should be able to follow the story to some point.
BTW I myself am a big fan of the related anime and I can recommend it to anybody who likes anime in general.