It was with a loli and shota. She has a crush on the shota. They were in the classroom and a rumor was discussed that says if a girl masturbates on her crush's desk they will be together forever or something. Another boy jokingly says she'll do it on his desk cause she likes him and proceeds to touch her down there and I think makes her cum. Her actual crush gets jealous from afar. Later she uses her crush's desk to masturbate and he catches her and obviously realises she likes him back. They end up doing it on the desk and at the end she realises she used the wrong desk.