'Wine guy' = a man who fashions himself as an expert on wines. He's drinking a lot of wine and using obscure, silly terms to describe various wines. He may call a wine's taste as 'woody with hints of asphalt and leather' or some other ridiculous description. In short, a 'wine guy' is a snob.

Maybe a sommelier. Urbandictionary.com has an entry for it, which anyone can agree or not with. It is a sort of wiki, and users can submit humorous definitions.

WARNING: dictionary.com is NOT a serious site for language learning! It is a PARODY site. It is in no way a resource for learning English. You should avoid it unless you're looking for a laugh.