Did a google search on sickest movies of all time. Found this description:
August Underground- Mordum
A character study in the sick: an amoral, putrid, masturbatory fantasy. Documents extreme deviant sexuality, torture, and murder, while unfolding a classic tale of a man and woman in love. However, the woman cannot give up her other lover, who also happens to be her younger brother. Exploiting the trio of killers and their deviant ways with issues such as child abuse, incest, rape, and their effects on the human psyche, this film will vomit all over you and leave you for dead.
There was also a clip posted on the site, but I just ate. If anyone watches this, let me know how it turns out. I'll claim pussy on this one.