A raging coke addict, typically female. A coke machine is the sort of girl that will do two lines so that she can sleep better, or down so many lines that your drug dealer will start getting suspicious of your own buying habits because you are dumb enough to supply her habit. Think Michelle Pfieffer in Scarface, or Scarface for that matter
Dude: That Lilo has a problem. It was 2 hours after last call at the club, the sun was rising and I saw her cut out and do 3 lines just because.
Dude 2: Yea she's a real coke machine