Based on the erotic games by Blue Gale Light. 
 
This is a collaboration of anime JK to Inkou Kyoushi 4: Doku mo Seika - Namaiki Model no Seikuhakusho with JK to Ero Giin Sensei from the same game company by Blue Gale Light. 
 
JK to Inkou Kyoushi 4 is now joining and collaborating story with JK to Ero Giin Sensei with a new title is JK to Inkou Kyoushi 4 feat. Ero Giin Sensei Namaiki Hamedoru Friends. Starting from Kashiwagi Hatsune from anime JK to Ero Giin Sensei moved to school in Takai Shizuka's from anime JK to Inkou Kyoushi 4. They were close friends, until finally Hatsune informed that her father was a high placeman, from which Shizuka planned to take benefit as her milestone. 
 
(Source: Translated and Edited from Nekopoi)

JK to Inkou Kyoushi 4 feat. JK to Ero Giin Sensei