Iu Koto Kiite, Sensei

Takano is the tutor to Iori, the son of a wealthy family. He has multiple part-time jobs but barely has any money to his name. While tutoring Iori was difficult due to the student's stubbornness, Takano is determined to have Iori open up to him, even with little progress. During one of his study sessions with Iori, Takano's landlord makes a call and threatens to evict Takano if he doesn't pay up soon. Takano is at his wits end on how to find a job to earn more money. Coincidentally, Iori overhears the conversation, and asks Takano if he needs money, to which Takano embarrassingly admits that he does and that he is willing to do anything. To his surprise, Iori suddenly throws money at him and says he will give Takano the money he needs as long as Takano does what Iori says—the first command being for Takano to masturbate in front of him.

(Source: Fantasista Inc.)