The Great White Wine
The basic joke of the 'whining' or 'wining' is that Benna understands that her problems are 'white people problems.' But actually, this is ironic, because her problems are very real and actually her loneliness is quite severe. So the basic irony of Eleanor and their whining parties is that actually, Benna is very lonely and she's afraid that she might not be able to be honest about that, like maybe loneliness doesn't really count as a real problem.
Eleanor and Gerard
Gerard doesn't know this, but one of the times they had sex, Benna pretended it was Eleanor having sex with her body, which is bizarre, and then they agree to abort the baby. How do we make sense of this strange association? Perhaps it shows that before Benna aborted the baby, she wanted to drive a wedge between her and Gerard. In other words, she hates loneliness, but she's comfortable when she's lonely, and she's not comfortable with the idea of mothering a child in a new family. So she has Eleanor "betray" her so she can stomach the separation.
Georgianna
Benna's imaginary daughter is certainly an ironic feature of the novel, and the parallel between the imaginary child and the real child that might have been is a strong one. The irony indicates the limit of Benna's ability to provide herself therapy in the form of play and imagination.
Darrel, the ironic truth
When Darrel enters Benna's life, she has to learn about race again, because the perspective she took on race didn't do good with the facts of other people's suffering. Therefore Darrel's suffering represents the ironic introduction of the truth into Benna's life. "Everyone is suffering in different ways." Hopefully one day this knowledge will help Benna to understand that our suffering makes us all into one big family, because we're all in it together, so she is not alone, even when she is.
Existential loneliness
The irony of existential loneliness is that it's true. By the time a person discovers that no one will ever truly understand them perfectly, they also realize that they'll never be perfectly loved by anyone, and the loneliness from that knowledge is severe. Ironically, it hurts just to exist. But nevertheless, there are ways of dealing with that fact and ultimately, even though Benna and Gerard's sex was awkward and existential, it was still a connection. So even though we can't perfectly understand each other, we can provide each other company and emotional support.
