Hello. Please help me in my search. Here is the plot.

The main character is a sexy girl, most likely a gyaru, but I'm not sure if she had a tan. In the beginning, after having sex with her boyfriend, she receives a stylish purse from him as a gift, then immediately leaves.
She has problems with studies, and one unpopular guy helps her with the preparation for the exams. This guy eventually falls in love with her and the gyaru decides to reward him for help by taking his virginity. I think this scene take place in the school roof.
In the final scene they meet again after she passed the exams. She says that now they have plenty of free time for fun, and abandons a purse gifted by her ex-boyfriend. The End.

Found it. It's Himitsu no Manabiya from collection Aimitsu Carameliser by 212.