The term originates from the word used to describe theatres that were known to screen such movies.
The term has now been repopularized through Quentin Tarantino & Robert Rodriguez movie using that particular name.
Dude 2: "Which one? Texas Chainsaw Massacre, Thriller, Cannibal Holocaust, The Beyond, I Spit On Your Grave, Last House On the Left, The Big Bird Cage, I Drink Your Blood, Bloodsucking Freaks, The Toolbox Murders, Superfly, Blacula, Dr.Blackenstein, Zombi Flesh Eaters, Virus, Mondo Cannibale, Porn Holocaust, Faster Pussycat Kill Kill, Supervixens, Beneath the Valley of the Ultra-Vixens, The Illsa Trilogy Box or the various Emanuelle flicks with Laura Gemser?"
2. Any movie fitting above description.
"no it wasn't it sucked to the moon and back"
"no it didn't"
"ya, it did"
and so on