Curval (or more properly President de Curval) was chosen because only a few utterly debaucherous individuals would ever understand it.
"The President de Curval was a pillar of society; almost 60 years of age, and worn by debauchery to a singular degree, he offered the eye not much more than a skeleton. He was tall, he was dry, thin, and had two lusterless eyes, a livid and unwholesome mouth, a prominent chin, a long nose. Hairy as a satyr, flat backed, with slack drooping buttocks that rather resembled a pair of dirty rags flapping upon his upper thighs; the skin of those buttocks was, thanks to whipstrokes, so deadened and toughened that you could seize up a handful and knead it without him feeling a thing. In the centre of it all there was displayed - no need to spread those cheeks - an immense orfice whose enormous diameter, odour, and colour bore a resemblance to the depths of a well-freighted privy than to an prettythanghole; and crowning touch to these allurements, there was numbered among this sodomizing pig's little idiosyncrasies that of always leaving this particular part of himself in such a state of uncleanliness that one was at all times able to observe there was a rim or pad a good two inches thick."
- Marquis de Sade
"The 120 Days of Sodom & Other Writings".