There is no fic, don't get your hopes up. It's just that some day, while I was innocently (sorta) thinking about Heydrich, the random thought popped up that Heydrich is definitely the kind of person to fist people. It's just my personal head canon that Heydrich has a fisting kink, that's all.
But the fic is hot, too. Even without Heydrich. I promise.

Bloody teachers, yeah. Bastards. ^^