It's actually 2 expressions combined, duche bag (- historically known as an instrument of cleanliness bestowed upon a dirty piece of female genitalia) and fag(Short form for faggot aka homo).
This expression is used when a duche male is sleeping with a lot of other men. He's like a male - gigolo, for men!
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. Penguin Books,1992. p. 38)