"
You go, girl!"
To be flamboyant is to take all the stereotypes of whatever it is you're doing to the extreme, either to be funny or to (possibly unconsciously) poke serious fun at it. To be a flamboyant homosexual means to do the "We're here, we're queer" in your face thing.
To kiss your boyfriend in public (if you're a guy) is not being flamboyant. To call attention to yourself doing such, however, -is-.