I am looking for a specific doushinji?

[zaphernith]

It involves a boy and a girl where he stood up protected a her from bullies or classmates after school when they were very young children. Now she follows him everywhere and she grew big boobs and stuff. He finds her annoying because she stands so close behind him that her boobs keep bumping and pressing against him giving him hard on and other classmates make fun of him. In the later pages, she decides to help him with his pants problem. That's pretty much the premise and I don't know the name of the doushinji at all. It is in Black and white. I think both the boy and the girl are blonde (well as it seems in the black and white art style) I'm not 100% on the boy but the girl is blonde.