Isekai de Dorei ni Narimashita ga Goshujinsama wa Watashi ni Yokujou Shimasen

Synopsis

6 years ago, Chika found herself in an unknown world and was promptly forced into a human trafficking ring. She was later bought by the stern-faced Douglas, a famous and powerful knight. At that point, Chika thought she would be sentenced to a life of serving her master's every whims, no matter how perverted... but Douglas can't get it up?! It seems that in the past, he was captured as a prisoner of war, and an experience with a "male slave" (really Chika with short hair) traumatized him to the point of impotence. While Chika is happy to do his chores and be doted on by him, his sexual trauma is a sore point for her. Will she ever be able to completely satisfy him, both as a maid and as a woman? (Source: Anime Planet)