Dirtybird is equated from the angrybirds series and is a play on that. It is when you eat a woman to creaming themselves lick it up and spit it in their mouth. Like a bird.
The Dirtybird, Dirtybirds (when Lesbians do it) Dirtybirdin.
Guy 1: Have you heard Sasha got the dirtybird the other night.
Guy 2: I did the dirtybird once