Sibling incest

[jain]

I'm looking for novels involving consensual sibling incest. The "consensual" doesn't have to mean healthy or happy by any means; I just don't want books about rape or other sexual abuse by siblings. I've already either read or have on my list The Carnivorous Lamb by Agustin Gomez-Arcos, Gemini by Michel Tournier, A Density of Souls by Christopher Rice, The Brothers Bishop by Bart Yates, and the Doctrine of Labyrinths series by Sarah Monette and, of course, Flowers in the Attic.

I'm most interested in suggestions for brother-brother or sister-sister incest fiction, but I'm also willing to try recommended books involving brother-sister incest.