"e.f. or f.f?"
Alleged to be old Navy slang, meaning, "You wanna get some real food or some tail first?" Occurs in _Time Enough for Love_ by Robert Heinlein. When Dora, "The Adopted Daughter," propositions him, Lazarus asks her "E.F. or F.F.?" She answers, "Both," which is in character for her and also has multiple meanings.