What is this manhwa called please?

What is this manhwa called please?

This teacher confiscates a raunchy book from one of his students and after he reads it, he ends up in the story. It’s a fantasy old-timey land and he first encounters a demon lord who wants to fk him but he’s rescued by a blonde priest. Then they set out to find Ben the mage who wants to fk him too (basically everyone and everything wants to fk him). He finds out he’s the Hero of the story but he’s actually taken the place of the real Hero from the story who is a scrawny femboy who is fked by everyone and everything but in a not nice way. Teacher guy ends up letting all of them fk him so they can feel better and grow as characters lol. Spoiler: he ends up falling in love with the demon lord