https://www.dlsite.com/maniax/work/=/product_id/RJ01326905.html
RAW: https://e-hentai.org/g/3295223/b18ebc2ca6/

[Synopsis]

Girls have an organ that exists solely to feel pleasure. Yes, that organ is the clitoris.
One day, the protagonist Masafumi Tanaka picks up an item that can touch a girl's clitoris as he pleases.
Tanaka, who is frustrated with the disciplinary committee chairman Miyuki Hasegawa, who hates anything erotic, attacks her with a cotton swab vibrator, toothbrush and other things during school classes and at home!
Furthermore, in order to turn the disciplinary committee chairman into a slutty woman, he begins training her to enlarge her clitoris!
In addition, an aphrodisiac is applied to her and the chairman, unable to resist, indulges in masturbation at school.
Tanaka calls the chairman to an empty classroom using a picture of her masturbating and makes further erotic demands.
The chairman desperately resists but there is nothing she can do with her clitoris exposed...

Base +25