How can you write if you cannot imagine something in all its horrifying, gruesome, most intimate details. No matter how taboo the topic, the writer must write about it without hesitation or reservation. If we censor our writing, so it is only appealing to the masses, then we limit ourselves and our ability to tell intricate stories. Our ability to live inside our characters, to feel their emotions, to breath as they do, is what makes the tragic hero, the despicable villain, the cheating husband, the buoyant teen. Without our ability to see as they do, feel as they feel, emote as they emote, we just have soul-less avatars filling prolix pages between two artfully constructed covers.
If the writer is inhibited, then their writing will be the same, and if the writer is embarrassed and holds back, this will show. Do not be reticent, instead write as foul mouthed as your character wants to be, allow your character to be who they are supposed to be, how you envision them in your head. I for one think back to all the books that were banned, and, well, I wouldn’t mind my work being put on the shelf, nestled next to those authors.