Nam Budoo is brownish somewhat thick liquid. It is made from fermenting fish in salt in a crock and let the fermented fish sit in the sun for a few months. The smell is quite strong. You can find nam budoo in a bottle (that resembles ketchup's) at many Asian markets.
The sauce will settle with clear brown liquid on top with denser sauce on the bottom. Shake the bottle before using. There is no need to refridgerate the sauce because it is full of salt.