Not only in Argentina an invitation for coffee means sex... I remember this episode of Seinfeld:
George:She invites me up at twelve o clock at night, for coffee. And I don't go up. "No thank you, I don't want coffee, it keeps me up. Too late for me to drink coffee." I said this to her. People this stupid shouldn't be allowed to live. I can't imagine what she must think of me.
Jerry: She thinks you're a guy that doesn't like coffee.
George: She invited me up. Coffee's not coffee, coffee is sex.
Elaine: Maybe coffee was coffee.
George: Coffee's coffee in the morning, it's not coffee at twelve o clock at night.