Bend One's Elbow Meaning

(idiomatic) To drink alcoholic beverages, especially at a public house or bar.

Example: 2002, Jacques Stephen Alexis, In the Flicker of an Eyelid, page 32
  One day is no worse than the next for El Caucho; so it's a whim when he starts bending his elbow or ties one on. When he is really "plastered," El Caucho looks grim, but he isn't really nasty.