Oboreru Kemono no Koibito

Eight volume in the Kemono series. Kazuki, the young master of Toudou Group undergoes training on becoming the heir of the company per his father's instruction, which finally drives his tutor for 12 years and now lover, Chiharu, to the brink of insanity and takes matters into his hands! How far would Chiharu go and how much could Kazuki tolerate from his beast lover? (Source: Fantasyshrine)