You can always tell a B-movie that takes BDSM for a theme is gonna be a stinker when it quickly becomes clear that the filmmakers don't know the difference between bondage and SM, because they use the terms interchangeably. If the plot involves an SM snuff flick, you know it's gonna be an evil stinker.
Primal Instinct is the story of a parole officer investigating the death of her sister, who was a bondage site model. The portrayal of the bondage site reveals that the creators had never been on the Internet, much less visited a porn site, and had gotten all their info about what porn sites are like from the real-life equivalents of Maude Flanders.
This film is even more mean-spirited, stupid and ignorant about its subject matter than 8mm was. (8mm also deals with an investigation of the death of a professional woman specializing in BDSM whose death shows up in a snuff flick.) Primal Instinct is not the worst movie ever made but it does suck in every respect. Michael Madsen and the female lead do their best, but god, it just isn't even close to being enough to stand down the cretinous dreck that's being shovelled here.