「お姉ちゃんが男と上手にキスする為の練習…付き合ってあげよっか///」東京から久しぶりに帰ってくる妹は、私と違って行動的で――――昔から、ちょっと羨ましかった。「ねぇ、お姉ちゃん彼氏いるの？？」「へぇ～、お姉ちゃん、おっぱい大きいし、メイクも変えたらめっちゃモテそうなのに」奥手で人見知りな姉’陽菜’は恋愛はおろか、男性と話すことも苦手な陰キャ地味子。「お姉ちゃんにメイクもファッションも…エッチも、全部教えてあげるよ」無邪気に微笑む妹に流され、陽菜は妹と、ファーストキスをする――――。恋愛経験ゼロ。男性が苦手な地味姉を性と快楽に目醒めさせるレズ沼姉妹セックス！由衣陽菜 初レズ作品！
"Shall I help you practice kissing a guy properly, big sister? ///" My younger sister, who had come home from Tokyo after a long time, was more outgoing than me—and I'd always been a little envious of her. "Hey, big sister, do you have a boyfriend??" "Wow, big sister, you have big boobs, and if you changed your makeup, you'd be super popular." My shy and reserved older sister, Hina, is a plain, introverted girl who's not even good at talking to men, let alone romance. "I'll teach you everything, big sister—makeup, fashion… and sex too." Swept away by her younger sister's innocent smile, Hina shares her first kiss with her sister. Zero romantic experience. A lesbian sisters' sex swamp where a plain older sister who's bad with men is awakened to sex and pleasure! Yui and Hina's first lesbian work!

– JavGG.net