Whether you've read everything there is to read here or if you've decided it's not for you and want to hunt elsewhere, these following paths should lead you someplace exciting.
A relatively new and growing site, also hosted at asstr.org. The stories are great for fans of scat-sex, and many other themes are covered too, from anal to domination.
An impressive and rapidly growing site by my good friend, Tom. It
includes stories from Tom himself and his girlfriend Emma, all naturally with a
strong emphasis on anal sex.
There's also a collection of stories by other authors, all featuring sodomy and often in conjunction with other kinky activities, e.g. scat, incest, bi-sexual, etc. Highly recommended!
Although sadly no longer free, this enormous site does have an impressive collection of erotic literature from hundreds of different authors. The primary themes are incest and underage sex, but there's pretty much every category of kinkiness covered in these countless words of depravity.
A huge collection of gay and bisexual erotic literature, some good, some not so good.
Apart from it's prudish refusal to include stories involving characters under the age of 18, this is generally a very good archive of erotic literature.