Eventually Sylvia stumbles home to grampa and her little brother and identifies the filthy hippies as her attackers. Naturally gramps grabs his shotgun and heads out to the abandoned hotel where the hippies have holed up to administer some country-style justice. It goes about as well as you'd expect. The hippies beat him up and humiliate him but they also give him a free hit of acid, so I guess he comes up about squits. The chubby kid manages to take gramps home where he and Sylvia have a pretty hilarious discussion about "that L... whatever-it's-called". Grampa completely fails to have an psychedelic acid freak-out, although in a deleted scene he is visited by the ghosts of the boy's dead folks (offscreen). Worst trip ever.
The next morning he's moping over his breakfast, wondering what to do about these shameless ruffians (calling the police comes to mind) but it turns out that the kid has decided to take matters into his own hands. After killing a rabid dog he injects it's blood into a bunch of meat pies and sells them to the filthy hippies. Uh yeah, I'm not kidding. Seems like a pretty fucked up revenge plan, especially since it's only later that he asks his sister what rabies actually does to people. She responds: "They go crazy and die, why do you ask?". No reason, sis.
The filthy hippies messily devour the meat pies (they come in a pastry shell for a reason, you slobs) and pretty soon they've all got the taco shits, big time. The black guy is the first to succumb to the illness (of course he is), and pretty soon he's stabbed one of the other hippies to death and is chasing around the rest of them around with an axe and a severed foot. It's not long before they're all displaying typical symptoms of rabies: murderous impulses, severe overacting, and the desire to smear shaving cream on your lips.
The rabid hippies scatter and cause havoc all over town, and they were into animal sacrifice and ritual mutilation before they went crazy, so you know it's going to be some brutal shit. Horace kills a couple of hippie-hating locals, an adorable deaf-mute hippie (played by Lynn Lowrie, who was also in George Romero's similar film The Crazies) cuts off an old woman's hand with an electric carving knife and a knocked-up hippie stabs herself in the stomach to spare her baby the same horrible fate (although I think she never actually had rabies so the joke's on her). Things really start to heat up when some local construction workers pick up a slutty rabid hippie and pretty soon she finds herself the center attraction at a large-scale gangbang that infects them all with rabies (among other things, I imagine).
None of this is ever genuinely scary, of course. The minimal yet wildly inappropriate soundtrack doesn't help, which consists of (aside from some fittingly psychadelic bleeps and blorps) some wacky chase music that kicks in during tense moments. I'll spare you the spoilery details of who lives and who dies, but needless to say by the end of the film Horace Bones is gleefully waving around a paper-mache severed head. The film ends in a wholesale slaughter of the infected by the local cops. Although the film ends rather abruptly, the DVD contains an alternate "downer" ending that is far more satisfying.
This film was originally named Phobia, which makes sense, but the studios gave it the stupid name I Drink Your Blood so it could be shown as a double feature with the 1964 zombie film I Eat Your Skin (aka Voodoo). It was the first film to be given an X-rating based solely on non-sexual content and was mercilessly cut to ribbons by various censorship bodies, so naturally it has developed a cult following. It was finally released in a fully uncut version in 2003, marking the instant at which everybody lost interest in the film. It isn't particularly gory by today's standards and aside from some icky animal cruelty (what is this, an Italian cannibal film?) there isn't anything particularly shocking.
To be fair it does have it's moments of craziness and hilarity and there's an undeniable charm to the clumsiness of the dialogue ("All you care about is your damn dam!") and the hamfisted way all the characters are portrayed, from the horn-throwing Satanists to the "aw, shucks" country folk. In the end, though, like SADOS itself, this is a cult following that is largely undeserved.