Have you ever wondered how the word "douchebag" acquired its secondary, now more common meaning?
After all, the original definition of "douchebag" is of a feminine hygiene product. The word "douche" is common in many languages, meaning "shower" in French and elsewhere. Nothing exactly pejorative here.
According to the ever-reliable Intertubes, it didn't begin to shift in meaning until the 1950s, when it appeared in "From Here to Eternity" (as an adjective: "that douchebag nose"(!)). In 1953, Henry Miller's "Plexus" features a character named Minnie Douchebag. In 1964's "Last Exit to Brooklyn", it was used as a noun to degrade a woman: "not like that fuckin douchebag he was with".
What happened over the next couple of decades is not clear. Slowly but surely, it started to enter the lexicon and shift even further, until settling on its modern definition sometime in the late 1980s. So today, when you say:
WHAT A COUPLE OF DOUCHEBAGS!
It's pretty obvious what you mean.