Lunatics: I Coated My Cheerful Girlfriend's Sister's Nipples with Aphrodisiac and Made Her a Sensitive, Horny Club Girl, Then Gave Her Nonstop Creampies While She Was High - Natsu Sano
Her younger sister was a pure and innocent high school girl, part of a club team. She had no boyfriend and knew nothing about men—yet curiosity and sexual desire began to stir within her. Without her noticing, he decided to test an aphrodisiac he had kept stored away for a long time. That night, he applied the drug to his sleeping sister's nipples, gently massaging them until she reached her first orgasm. From that day on, stealing moments when she wasn't looking, he made her ingest the aphrodisiac, plunging her into repeated drug-fueled sex. Her body became hypersensitive, reacting with tingling sensations, until she was reduced to wetting herself. Drawn deeper by her helpless state, he found himself increasingly obsessed with her.