The summer vacation...with a teacher in a vacant classroom. It is a sweet painful love affair that a girl often (o rly?) experiences. This is the sixth issue of the best-selling Cheese selection. Nine other stories are included besides the title story written by Sugi Emiko.

From MangaHelpers:
This is a story of a group of college-age people who struggle with gender and sexual identity.
Yuki (nicknamed Yoshiki) is a girl, but she is terrible at 'being feminine.' She mostly dresses like a boy and is often mistaken as one. However, she has to wear a skirt and imagine being dominated by a guy in order to masturbate. Nagao Mikako seems young and innocent, and she uses that apparent innocence to sell her body as a fake 15-year-old. She knows her youthfulness can't last forever, but she enjoys tricking the men. Her friends have no idea of her sexual habits and believe her to be sweet and sheltered. Aiba Kaito is a pretty good-looking guy, but he wants to be Nagao Mikako. He often dresses as a girl, picking out clothes that mimic Mikako's style. Though he's into cross-dressing, he is still attracted to women. Will these young adults and their friends be able to handle their 'guilty secrets' and muddle their way through this confusing period of their lives?

1) Passion Kiss (Yokujou Kisu One night) -
Manatsu has a dream of an incredibly fulfilling kiss. "Who was the boy in my dream? That's the first time a kiss has made my chest ache." That's when Manatsu gets a feeling from her classmate, Morishima-kun -- the same feeling she got from the boy in the dream. Without thinking, and despite the fact she already has a boyfriend, she... (!!!)

2) Second Virgins (Sekando Vaajinzu) -
Kawori is prepped and ready to lose her virginity to Shunsuke... until he penetrates her and it hurts like hell. She wants him to stop, but he can't. They get into a fight and stop talking after that. Then, one and a half years later, Kawori gets coerced into attending a singles party -- and Shunsuke is there! ...As the boyfriend of Kawori's friend Nao? How will Kawori and Shunsuke handle their unresolved feelings?

3) Eternal Summer, Fleeting Summer (Eien no Natsu, Isshun no Natsu) -
The first love letter Takeshita Riho wrote was to Sakurai Touma, the class president she had a crush on from second to sixth grade, but the letter never got sent. ...Until now, when Riho's meddlesome friend mails it out. To Riho's surprise, Touma writes back and responds well to her feelings! He's just as Riho remembers him, and the way he writes makes it sound like those elementary school days were the most important of his life. What Riho doesn't realize is the heart-breaking (and tear-jerking) reason why...