(Eng.) Slang term for pornographic literature.
"Gross, you got my jazz mag all wet."
A specialist gentleman's publication often enjoyed lying down with the curtains closed.
Father: "There's a lot of banging going on upstairs, where's young Steven?"
Mother: "He's in his room, reading"
Father: "Hm, he's probably looking at a Jazz Mag"
Mother: "Good gracious no, he's not that kind of boy. He's probably just exercising, and he's never liked Jazz music"