My little sister has always been fond of me and will do anything to make me happy. Lately, she's escalated from handjob to blowjob, becoming more daring each time. Even when our parents are around, she teasingly shows off her blowjob skills, making me nervous. Ignoring my hesitation, she whispers like a devil, "Don't you want to do even naughtier things?" With a mischievous smile, she says, "I went ahead and inserted it," crossing the forbidden line. I tried to say no, but it was too late—I came hard inside her.