Hanbun Ageru: Bangai-hen

Burned out from a grueling end-of-the-year workload, middle school teacher Kurokawa transforms into the demanding Aggrokawa! This overtired alter ego craves nothing more than pampering. Meanwhile, his boyfriend Shiraki is torn. Knowing Kurokawa has a masochistic streak, Shiraki is tempted to push his buttons. But when Aggrokawa's seductive side comes out, he's determined to get to the bottom of what's "painful pleasure"...!

(Source: Leed, translated)