A back room at home, a friends place down the street, a relative's attic, any place for a planned sexual expirience. Different from a bathroom blowjob or dumpster quickie in that a slam venue is used for sex after more formal encounter, like a date, or after "watching" a movie. Mostly applies to people who live with parents, or others who don't approve of casual sexual expiriences and can't do it at their place of residence.
1: So what did you and her do after the movies?
2: We went back to my grandams place and did it in the basement, it's the perfect slam venue when my family is around my place.