あなたの精液くださいな ～私とボクとどっちがお好み？～

Sakurai Manato was a young man with a peculiar sexual quirk: due to past experiences, he could only feel arousal toward girls with underdeveloped bodies.
One day, a succubus named Teana—a buxom older-sister type—showed up at his doorstep.

“I need your help! Can you help me overcome my… sexual quirk?!”

Manato believed that with the techniques of a succubus, he could finally return to being a normal human. He pinned his faint hopes on this chance encounter.