The 4th volume of the popular series is now available! The infinite sexual desire of 6 frustrated office ladies runs wild with a machine vibe! Office ladies who straddle their own machines at the place they visit at work. Vagina, stirred by a strong piston, irresistibly spouts the tide and does not stop in search of heat. Plenty of sluts who seek ejaculation in the vagina themselves are super erotic.

Haruka decides to buy a vacation home to reclaim time with her husband, who is recovering from an injury. When she visits the property to inspect it, she is led by the caretaker to the basement, where she finds an old diary. Inside is a candid account of the experiences of the diary's owner, Utako Maruyama.