You do mean, "Deuce Bag" And it's origin is the Latin word "Deuce", which means time, but. that has nothing to do with that term, The term "Deuce Bag" is an Insult, technically calling you an "Idiot" or "Moron" or even some times a "Dumb A#$"
It is an item of military equipment used to shower with in the field.
It's a black plastic bag that contains a gallon of water that is warmed up by the sun through the day and then hung above the head and you have a hot shower.
Dousche is French for shower.
a "duche" is a feminine hygiene product, usually an applicator filled with a semi-medicinal solution that is released into the vagina for cleansing purposes. The term Duchebag is a crude repurposing of this item as an insult.