You folks' "sickest" viewings bat mine by numerous long shots!
Back in the "pre" internet days (i.e. when internet porn wasn't as readily available as it is now), myself and a few friends ended up renting some porn which happened to cross the US borders before the 90s super-crack-down from the censor boards in Canada.
For example we managed to get one or two uncensored Max Hardcore vids from the early 90s... before the customs border patrols started censoring them to 30 minute long features!
I also remember two Rocco Siffredi "movies" in which the main "actress" in the film (she was basically the only female in the whole feature) was basically tossed around like a rag doll and yes, the infamous toilet dunking which in those days way unheard of (but now almost considered tame by today's standards).
In the internet years I clearly recall cowguts porn: Japanese people having sex amongst bovine guts (hopefully these weren't salvaged after the shoot to the local butcher shop!).
I also "recently" came across an official japanese video (i.e. 90-120 long) where for the second half of the video, the poor lady is clearly regretting her decision to appear in said porno, and yet they keep filming and going at it until the point where she's gagging, puking, and a twitching mess amidst a pool of cum and piss. Obviously they stopped at some point but they just kept filming all the way through, even after they "rescued" her and cleaned her up and tried to get her comforted back to "safety". Was was shocking for me was the fact that they kept filming and fucking her and peeing on her even though at this point it was clear she was concenting to any of this at all. I know that there is still way too much un-concentual activities happening in porn (Japan-European mostly) but again, the fact that they kept filming the whole ordeal remains quite shocking to me.
But then again I am a relative newbie when it comes to all things JAV porn and such!