Mr.hackl is a term used to define when a school teacher is a complete utter douchebag or when a teacher acts really queer,this term originates from an actual teacher named mr.hackl that is a complete douchbag and and the most idiotic person ever.
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi