It is the start of Takatoshi Tsuda's second year as the put-upon vice president of the student council and his sister Kotomi is entering school as a first year. New friends and double entendres are made.
 
(Source: Anime News Network)

Tsuda Takatoshi is about to begin his first year in Ousai Academy. His decision to enter Ousai was based upon it being close to his home and he paid no heed to the fact he'd be among the first boys to enter the recently gender-integrated school. 
On his first trip to school, Takatoshi is surrounded by girls; the train has nothing but girls, the walk to school has nothing but girls and once he finally arrives he is approached by a group of girls and summarily appointed vice-president of the student council and, as expected, he is the only boy there. 
Now Takatoshi finds himself surrounded by crazy girls who do nothing but horrify him with their candid conversations about feminine hygiene products and, what's worse, assume he's the worst kind of man, the kind who doesn't clean himself and watches porn all day long.

Tsuda Takatoshi, a new student in the recently gender-integrated high school, is asked to join the student council, as the vice president. Thus begins his days as the only normal person in among the 4 member student council officers...
 
Note: The first 15 chapters were published in Magazine Special. It switched to Weekly Shounen Magazine starting with Ch. 16, with the chapter count being reset. This entry still includes the first 15 chapters from Magazine Special.

The second season of Seitokai Yakuindomo.

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