As a writer you have a moral responsibility to be true to your art. Anything less is undeserving of your time and worse, undeserving of your readers. I am a firm believer in giving everything to your writing, even if this means that sometimes your themes, scenes and the language that you use might upset, offend and shock friends, families and loved ones.
If you are going to be genuine about what you're trying to produce and say, you need to be genuine in how you go about writing and what you write. And sometimes that means writing words, deeds and actions which might not usually come from your mouth in everyday life and company.
Books are about escapism, both for the reader and for you, the writer. It's an opportunity to let your imagination and your vocabulary go on holiday, cast off the shackles of boring life and run free.
Whilst dredging the dark recesses of your mind might produce things which surprise and horrify you, not forgetting the person reading your material, the results will always be far more honest, real and affecting when they appear on the paper, than if you try to write with one foot in the Mary Whitehouse camp of censorship.
I've written some dark stuff in my time; sexual assaults, hideous murders, graphic descriptions of war, torture. And do you know that in all the years I've been writing and showing people my work, not once has someone I know come back and said, "Oh Tarn you naughty boy!" However, I am sure they would have come back and criticized me if the work had not been fulfilling and written with honesty and belief.
Nothing I write is written simply to be gratuitous. Everything is carefully considered and penned for a reason. The reason might be to shock, horrify, anger or sadden, but it's always put down on paper with my hand on my heart, even if, occasionally, my other hand is in the gutter.
Just like in the best comedy, sometimes a beautifully placed expletive can work wonders with your prose.