[Azuma Takeshi(東毅)] Denpa Kyoushi (電波教師) - Vol.12 [2014-08-23]
Code:
https://www.sendspace.com/file/uq7eeu
VR (?) TG via magical girl transformation with no process involving Kagami, Sadamitsu and Seijirou, not sure if I missed other characters. Chapters 107 to 113 (+ omake) are included above.
Seems like Azuma Takeshi took some liberties for Vol.18, it didn't last so far.