Geboku Shigansha Munenori-kun

Hisaki, who has always prided himself on treating everyone equally, finds himself in a bind when Munenori, a straight man he just met, suddenly insists on becoming his servant. Though Hisaki values rationality and self-control, Munenori’s insistence stirs something within him, making it hard to keep his composure. Now, Hisaki must navigate the tension between his deeply held beliefs and the unexpected desires Munenori awakens in him...

(Source: Core Magazine, translated)

Note: includes one extra chapter.