Ok, while tubgirl make have gotten the crown for the grossest porn site..let me redirect your attention to this group of people....
http://www.ogrish.com/
Some of you may know it as oen of those kind of sites that post gory pictures and videos. But when I checked out the site forum, turns out that there's even more shit. Some of the poster share some experience of jerkin off to gore pictures and videos. Personally, tubgirl can't beat snuff.