All Human High School AU: Locker Graffiti
I was reading the fic Uprising by Metallic_Shadows when I was reminded a fic I read a while ago. However, I don't remember much.
Details: Cas is trying to clean his locker after it has been vandalized with spray paint (or something) when Dean comes across him. Dean asks Cas if he needs help cleaning it up. Eventually the two of them get to know each and start to date. Later on, Dean confesses to Cas that he was the one to put the graffiti on Cas' locker, so that he could have an excuse to talk to him.
Details: Cas is trying to clean his locker after it has been vandalized with spray paint (or something) when Dean comes across him. Dean asks Cas if he needs help cleaning it up. Eventually the two of them get to know each and start to date. Later on, Dean confesses to Cas that he was the one to put the graffiti on Cas' locker, so that he could have an excuse to talk to him.