The highlighted passage involves Lula's attempt to seduce Clay and to tempt him to indiscretions with her sensual dance.
Yet, even as Lula beckons Clay to join her, he remains resolute in his decision to reject her advances. Notice how Lula tries to goad Clay into displaying his rage by insulting him: "And that's how the blues was born. Ten little niggers sitting on a limb, but none of them ever looked like him. [Points to CLAY, returns toward the seat, with her hands extended for him to rise and dance with her." Her actions epitomize the racist belief that black men lack self-control and can be easily provoked to feral or brutish behavior.
Lula is the antithesis of Senta in Wagner's The Flying Dutchman. In The Fying Dutchman, it is supposedly Senta's purity and loyalty that saves the Dutchman from eternal sojourn on the seas. In his play, Leroi Jones turns this on its head: Lula exemplifies the worst of human nature. She personifies the racist colonial attitude that will doom someone like Clay to obscurity and degradation. Although Lula portrays herself as a savior of sorts, she is really a predator: "As she sings she rises from her seat, still throwing things out of her bag into the aisle, beginning a rhythmical shudder and twistlike wiggle, which she continues up and down the aisle, bumping into many of the standing people and tripping over the feet of those sitting. Each time she runs into a person she lets out a very vicious piece of profanity, wiggling and stepping all the time."
Lula manages to hide her intent for a time, but her true purposes are exposed towards the end of the play. Notice that Lula abuses every passenger along her path; she is equally dismissive of both the white and black passengers on the train. Her actions signify her intent to destroy anyone who refuses to bend to her will; Lula is a faux savior and is not to be trusted. She aims to goad Clay into displaying reckless behavior because her true objective is to destroy him. In the passage, her contempt for Clay is evident. Leroi Jones seems to be making the point that black men like Clay must look to themselves if they hope to achieve a measure of success in their lives.