Thanks to my parents' remarriage, I got a shy, cute, busty little sister who's an only child like me! I blatantly harassed her, knowing she'd be too timid to resist. Just as I expected, she couldn't strongly refuse when I tried to force a kiss, but to my surprise, she rejected me! However, I couldn't back down at that point and forced a kiss anyway. Then, the sister who had been resisting gradually relaxed her guard and even put her arms around my neck herself! This was it, I thought, but her true nature was unexpectedly wild, and after I came inside her, she kept asking for more, which was quite a challenge!