The Rice University Neologisms Database

To greedily swallow a liquid in large amounts causing gulping noises to occur. "Gunkin" is similar to the word gulping because both words mean to take a liquid into the mouth and swallow. However, the action of gunkin a drink emphasizes the sound that is made (specifically in one”s throat) by the person consuming the drink. For some reason the word gunkin does not bear any similarities to the informal word “gunk”. One might speculate that the word “gunkin” comes more from similar verbs such as guzzle or gulp, with the ending of “kin”.