HUNTB-104 ``If you teach me how to study, I'll teach you something naughty in return.'' A private lesson in exchange between my sister-in-law, who is so slutty that her grades are disastrous, and me, a virgin who is obsessed with studying.

One day, my sister-in-law, who had never studied at all, suddenly announced that she was going to university. - At my mother-in-law's request, I decided to teach her... - This is impossible! - I can't do it! - My sister-in-law is so stupid that I give up. - However, my sister-in-law says that if she teaches me how to study, she will teach me naughty things... - I'm a hard worker and good at studying, and my sister-in-law is a slut, so I'm good at sex... - Result: Win-win equivalent exchange established! - A secret private lesson begins!