It was a multichapter fic (possibly WIP), the boys both cops or private detectives going undercover in a school to uncover a neonazi group. Brian pretended to be a teacher and Justin a new kid with fake nazi tattoos, reading "Mein Kampf". (He had to demonstrate his acting abilities by impersonating a hustler first.)
It was dangerous and very taxing on both of them. At some point J climbed into B's room at night for some human touch.
I'm sure I read it. It is a classic. When one of you smart cookies tells me the title and author's name I will surely slap my forehead and roll my eyes...
Yep, slapping and rolling. It is "Broken Open " by Gina Marie (not that of thesalmondean by the same title).