A Secret Lesson With My Younger Sister Raw

“I heard you’re good at sex.” Jinyoung, known among his friends as “Sex Professor,” is actually inexperienced and as single as could be.

However, when his 20-year-old sister, Bom, questions him, Jinyoung pretends to be experienced and lies. After that day… Every night, my sister now comes to my room without our parents knowing. This is a problem.