The impression I get from this song is that it's supposed to be ironic. The narrator is so tired of males constantly coming on to her in a pushy way (and they probably don't expect anything to actually happen), and eventually she gets fed up and challenges them right back (calling their bluff).
Random male fan: "I want you. insert lewd gesture
Rihanna: "Okay, fine. You want me? Then let's go."
The impression I get from this song is that it's supposed to be ironic. The narrator is so tired of males constantly coming on to her in a pushy way (and they probably don't expect anything to actually happen), and eventually she gets fed up and challenges them right back (calling their bluff).
Random male fan: "I want you. insert lewd gesture Rihanna: "Okay, fine. You want me? Then let's go."