G-Cup Sisters! -Imouto Darake no Sakunyu Gakuensai | Gカップシスターズ！ ～妹だらけの搾乳学園祭～

A new teacher Ukima Sousuke, it is assigned to the Kamonomiya school which is an old school of oneself, it aggressively tries to work as the teacher of admiring. Such Sousuke, it is an elder brother at home who has three younger sisters.

Eldest daughter Himari of natural airhead group. Second daughter Yuzuki that depends too much in steady. Third daughter Mio to which elder brother is teased like devil.

Close younger sisters to the elder brother from an early age, three people enter the old school of the elder brother all together. And when the elder brother goes for one's post as a teacher, Brother complex style that always follows around in school not to mention from getting up and commuting to and from school.

However, has all the growth gone to the chest, the height does not grow but the breast grows up to G cup of the huge breast. Therefore the brother complex action that doesn't change from an early age, it has come to stir up the desire as a man.

As an elder brother, as a man, a certain day when campus festival has approached holding complex desire to younger sister. To Sousuke that remained after school, younger sister Himari expresses tears.

[I... the breast has come to go out! What shall i do, Onii-chan...]

Though it calms, do not have an idea how it is necessary to do and Sousuke to be at a loss, himari opens mouth timidly.

[You know... Onii-chan... um, onii-chan squeezes the breast... no good?]

I rub the chest of the woman despite a younger sister, to squeeze mother's milk out... it is not to be permitted as a teacher! To Sousuke where it tries to remain by common sense and reason, himari asks for the breast of G cup by the drawing upturned eyes.

[Request, Onii-chan... i can ask for such a thing... there is only Onii-chan...]

Reason is destroyed disappointing in the word, sousuke which consents to take the request of the younger sister and squeezing mother's milk. A low height in a lovely figure. And the size of the chest is G cup. It is asked by such younger sisters, how far does the reason of Sousuke to squeeze mother's milk keep...?