Kusatta Kyoushi no Houteishiki
English title: Bad Teacher Equation
Japanese title: 腐った教師の方程式
Alternative titles: Rotten Teachers Equation
Type: OVA
Source: Manga
Episodes: 2
Status: Finished Airing
Aired: Nov 25, 1994 to Nov 24, 1995
Duration: 28 min per ep
Rating: PG-13 - Teens 13 or older
Studios: J.C.Staff
Genres: Boys Love, Comedy
Themes: Adult Cast, Workplace

Atsushi Arisawa enrolls at Jougaouka High School to be near Masami Shibata (Ma-chan) who was his childhood crush. Unbeknownst to Atsushi, however, Masami no longer works at the school and his brother, Masayoshi is now the nurse. Atsushi mistakes Masayoshi for Masami and is horrified because to him, it appears that Masami's personality has done a complete 180. Add to the fact that Atsushi's friend, Kouji Inagaki is totally in love and constantly trying to make-out with him, Atsushi's life at Jougaoka is hell..until he starts thinking that maybe the new Ma-chan isn't so bad afterall and that, maybe he actually likes the way Ma-chan is now. Until of course, he finds out that Masayoshi isn't Masami. 

(Source: ANN)