My girlfriend won't let me have sex unless I create the right mood, so I splurged and invited her on a hot spring trip, but to make it harder for me to have sex with her, she brought her sister along, and I thought I was screwed -- or at least I was wrong. But it turns out her sister, Mio, is a secret nymphomaniac, and despite her innocent appearance, she seduces me as soon as we arrive at the inn, saying, "Touching myself with my hand doesn't count as cheating, you know? I don't know, though." I felt guilty, but I gave in to her sister's devilish temptation, and she kept jacking me off throughout our three-night stay, and I was completely won over by her Ke'ai face, whispered dirty talk, and technique.