I saw this manga in Hitomi. I've tried searching using various tags, but I failed, and now I'm looking for someone who knows this manga by sharing a story. The story is a fragmentary story, not a whole story.

Student couples have oral sex before going to school. After that, the man wraps semen in the girl's mouth.
But men don't allow you to swallow semen.
The woman goes to school with semen in her mouth.
After that, even when the woman is greeted by her friend, she does not open her mouth and accepts the greeting with a smile.
Before the first period begins, she quickly enters the public restroom, opens her mouth, and takes pictures of her face and semen.
It was only after taking the picture that she was able to swallow semen.

This is in the beginning, and I remember that after that she was asked to do a lot of pervert favors by her boyfriend.

Please let me know if you know any mangas of this content!

Also, please let me know the site where I can ask questions by posting these comments.