Yusuke unexpectedly witnessed his parents' nighttime lovemaking. He was shocked to see his mother, Chisato, with a look of a woman he had never seen before. He couldn't bring himself to be happy about the possibility of having a younger brother or sister. Instead, an intense jealousy welled up inside him. He wanted his beloved mother to love only him. Wishing this, Yusuke was overcome with the urge to fill Chisato's vagina, which had already been filled with his father's semen, with his own sperm. Yusuke forcefully pinned Chisato down and told her, "I'll make your mother pregnant," as he poured his hot semen into the deepest part of Chisato.