It means she smokes weed, unless (of course) she is using in its literal sense.

Police see this on marketing ads.Bad enough want to shut down pay to play

But of course there are those who are speaking of other drugs.  

 
I'm occasionally asked if I'm a "party girl" and being the smartass I am I've always wanted to reply in the affirmative, then have my hotel room decorated with streamers and balloons, with a  big candle-lit cake placed prominently in the middle of the space.  

Then I can look at him with wide-eyed innocence, asking "Isn't this what you meant?"  LMAO!

Yes, this is the sort of thought which entertains me.