Trolling is the term derived from the word "troll," which indicates trailing a fish along a baited line. In modern culture, trolling refers to hitting on guys when you are out, by baiting them with a little information about yourself or a flirty comment, and then playing hard to get. By planting the "bait," a girl will subsequently "troll" and find herself surrounded by a whole crowd of boys.
The act of trolling is an art-form, generally reserved for hot chicks out at a bar and/or club. However, it is possible to troll in all locations, such as the library or a coffee-shop, though that is a skill reserved for only the most talented individuals.
Note: Not to be confused with the noun "troll" (an ugly chick) or spamming message board (whoever does that cannot certainly cannot actually go trolling).
Girl1: I gotta get my make-up and tight dress on so I can troll tonight.
Girl2: Gen, I know, there will be a lot of trolling potential, like last night. I saw you surrounded by all those hot dudes.
Girl1: Troll or die, Liz. You gotta rage to troll.
Girl1: They see me trolling...
Girl2: They hating...
Girl1: But actually. Hatahs gonna hate when you troll so hard.