Maria Holic. Volume 5 - Minari Endo

A cute girl who's afraid of guys ends up at an all-girls school with a - you guessed it - cross-dressing boy as her roommate! When Kanako ends up on trial for attempting to eat Yonakuni the dog, she forgets all about studying for the final exams. As a result, she ends up the first person in Ame no Kisaki's history to have failed all her classes. An emergency committee is formed, and Ryocho is appointed its head. She tells Kanako to leave for a week of self-study in the hope that she'll come back more mature and responsible - but how will her friends survive the week without her?