Akuyaku Reijou desu ga, Watashi wo Anata no Seidorei ni Shite Kudasai!

Chris-sama, the Ice Lady, is the villainess of a fantasy novel. I've been trying my best to help her avoid the inevitable breakup and other doom flags. But she says she wants to be my sex slave! Her first experience is sex-training at a cheap inn! She climaxes in a dungeon and gets covered in semen! She wants to be dominated, my pure and innocent slave. The adventure story of an innocent but naughty lady slave and her isekai-reincarnated servant-master!

(Source: Bishoujo Bunko, translated)