"Sperm donation"... A special act in which an ordinary man provides his sperm for couples struggling with fertility. [First couple] Married for four years. Though her husband gently said, "If Yuichi is okay with it, then I am too," Aina struggles internally—aware that her husband wants a child soon due to her age, while she herself isn't as eager. She begins the oil massage calmly, but gradually grows curious, her body becoming increasingly sensitive. [Second couple] Married for three years. Akari strongly desires sperm donation through timed methods, but her husband sends her off reluctantly, viewing it as "loveless work." Contrary to his expectations, as she interacts with the donor, she becomes deeply engrossed in the act, repeatedly craving more and more sperm. [Third couple] Married for two years. "Since it's ●● donation, shouldn't we get someone genetically superior? Someone handsome?" Akari convinces her husband, prioritizing efficiency over his preference to avoid timed methods. Upon meeting the donor, she's instantly captivated by the handsome man, leaving her husband behind as she indulges in the oil massage. [Fourth couple] Sakura, married two years, desires timed sperm donation—the method with the highest pregnancy rate—and her husband agrees, allowing her to undergo the treatment. Sakura starts the oil massage composed, but soon can't withstand the stimulation, letting out sweet moans and reacting passionately, her ecstasy echoing throughout the room. Though sperm donation was the sole purpose, what unfolds is four hours of erotic footage capturing four beautiful wives surrendering completely to carnal desire.