Basically the same as "homie" "Holmes" "N*gga" Whatever floats your boat, i don't mean the N word rascally, just as another synonym for "homie". I just personally think Duco sounds better, i recall hearing it more in NYC and origins may be of mexican or latin (american) heritage).

******side note, some use as one of those words you can replace any noun with the said word...(duco).

you and your partner's sexual fantasy combined into some hardcore stiff cock riding action all freakin day

to defaecate

Playing runescape throughout the early morning hours after having consumed a large amount of alcohol.

A name for a cool person

The best couple ever. It's couple goals, everyone would love to have a relationship like this with their crush.