From Yen Press:

Nanako and her two best friends, Akane and Shino, have been in the same class since elementary school. Now with the entrance exam just around the corner, the girls have big plans for spending their college years together as well. Unfortunately, those big plans hinged on all three of them passing their exams…Now Nanako and Akane are ichiroh, first-year students at the local prep school. Nanako is determined to do better next year, but it’s going to be a real challenge — the bossy dorm/shrine manager puts the pair to work as miko, Akane can’t kick her video game addiction, and the neighbor’s pranks are getting out of hand! With all this nonsense, Nanako will be lucky to get any studying done!

Iroha, a masculine girl, and Hifumi, a feminine boy, are siblings who have transferred to a different middle school and moved to their grandparents house. However, after the first night, much to their surprise... they've switched genders. The two are left feeling "delighted"...

Interpretations of Kakifly's K-ON! 4koma by various other mangaka.