Mayumi grew up in a very ordinary family. She had her first sexual experience in high school, worked as an office worker at a transportation company, and married a manager at a food processing company whom she met through a friend, after only a year of dating. Before that, she had had sex with 10 men, and would have relationships with men other than her boyfriends if the mood was right. They tried to have a baby, but after 7 years, the frequency of sex gradually decreased. Mayumi loved to drink and wanted drinking buddies. Once she was no longer criticized for drinking out occasionally, she started drinking with men she met at bars. One of them was Hyottoko Oyaji.