Hey sorry to post like this but I've been having no luck finding this story.

From what I remember of the fic, Hermione was dared to seduce Draco and so she did by disillusioning herself. She found him outside and seduced him. The next day she thought she had gotten away scot-free but he figured out it was her because she left a hair ribbon behind (she was wearing them during an earlier Quidditch game).

If anyone knows which story this is and can let me know that'd be super. Thanks!