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!
A term used by professional divers (see monkey fucking a football) to describe a particular person or organizations discombobulated attempt to complete a task. (Note the diver has air hoses and is underwater)