i think that sometimes words like "fuck" do work for the lust of the moment. After all even the most respectable well-brought up people occasionally want to f-k like dogs in the ditch.
I feel however as with the first novel I ever read of Tabitha King's that an author is making excuses for him or herself if I have to be shocked by curse word usage in erotic scenes in the very beginning of the book or story. I should find the story captivating enough to stay and read..not be talked down to like a rowdy adolescent. The writing itself must be lure enough to engage me. All the curse words or sexual terms in the world are not going to hide bad writing.
There are also such a limited number of those words and each is more or less 4 letters..while out there are a billion ways to describe touching a lover's breast..seems a shame to limit possibility. Certain words and terms are so overused that they lose any power they might've ever had originally.