R-18(2004)

R-18

16-year-old Rico Mitsumi looks like your average girl, but she actually has a very big secret: she's the author of the famous H column "R-18"!! Even though she sounds very experienced in her column, in reality she's a one hundred percent virgin! Unfortunately, this secret of hers was found out by a very handsome guy. And in order to keep his mouth shut, his conditions are either to pay him one million yen or pay with her body! Seriously?!

(Source: Flower Comics, translated)