A master hog is an extrememly large amount of chewing tobacco, usually grizzly wintergreen. It is all relative to the person throwing in the master hog so it can line your entire lip or take up a third of your lip.
Bro 1: hey bro, can you throw me that can of grizzly wintergreen right there? its time to throw in a master hog.
Bro 2: sure thing, bro. here you go.
Bro 1: Thanks bro, i also think it just so happens to be Chew Thirty. (Both Bros Fist Bump)