Renai Mangaka no Kawarekata

Riku, who has been living on the edge and will be attending a vocational school in April, was offered living expenses and a place to live by a drinking buddy on condition. Tired of his part-time job, Riku jumped at the offer. However, what awaited him at his new home was Haruki, a male BL manga artist who was extremely grumpy because of his hellish work. What's more, the condition is "to take care of Haruki who leads an unhealthy life," but suddenly, he was told to be a model, and he unexpectedly got a boner in the midst of it...!

(Source: Oakla Comic, translated)