While Dad and Mom are away on a hot spring trip with their local community association, younger sister Mai becomes more proactive than usual. Filled with feelings for her older brother, she follows him everywhere—through the bedroom, kitchen, entryway, bathroom—teasing him with naughty antics. Throughout the day, without pause, they engage in repeated sex, climaxing over and over, thoroughly enjoying themselves. Mai sincerely expresses her amazement, saying, "Big brother, you're amazing! You shot so much milk, and you're still ready to go?" This work portrays the special bond that forms between siblings in the absence of their family, along with pure, heartfelt romantic emotions. *No performers in this work are under 18 years of age.