Love triangle 1

The heroine is named Kinoshita Sakiko. She is 20 years old, and a college student. She is totally in love with her 28 year old university professor, Chifyu-sensei. He is tall, moody, and handsome, with short dark hair and sexy eyes. Unfortunately for Sakiko, he always refuses her very aggressive displays of affection. Yet she never gives up. Even when faced with a housing crisis, Sakiko goes to drastic lengths to earn money so she can stay in the area and continue her pursuit of her teacher. However Sakiko isn't very bright when it comes to making money. She actually tries to sell herself on a street corner!! But her price is too high, and no one is interested. Then she meets a guy on the street named Natsuo. He is also really cute, with long blond hair. He is interested in Sakiko, and after one really great kiss, he takes her to his apartment. Things are starting to get steamy when they are interrupted by the arrival of Natsuo's brother. Guess who it is?