"That will only happen if I have a bout of amnesia or if I feel like mooning someone in the audience"

Daryl Hannah's quote, "That will only happen if I have a bout of amnesia or if I seem like mooning someone in the audience", is a brilliant and vibrant expression that can be interpreted in a few different ways. At its core, this declaration suggests an action or event that is highly not likely or would just take place under severe or funny circumstances.

The mention of "a bout of amnesia" suggests that the speaker would need to forget their concepts, previous declarations, or commitments to engage in the indicated action or habits. In other words, it would need them to lose touch with a vital part of their identity or memory. It recommends a not likely situation where the speaker willingly discards their recognized mindset or decision-making framework-- a state which is both uncontrolled and improbable, akin to struggling with memory loss.

The second part of the quote, "if I feel like mooning somebody in the audience", introduces a more amusing and rebellious component. Mooning, which involves baring one's butts normally in jest or as a type of protest, is a socially non-traditional and strong act. By declaring that the not likely event would occur if they were inclined to moon the audience, Hannah injects a sense of playfulness and irreverence into the declaration. It recommends embracing a mood that's spontaneous, defiant, and ready to shock or surprise others.

In general, the juxtaposition of amnesia and mooning produces a scenario where the speaker underscores their unwillingness or refusal to act unless under conditions that are, respectively, outlandish and whimsically defiant. This makes the declaration a declaration of company standing on a concern, conveyed through humor and vibrant imagery. Hannah utilizes this colorful language to stress her dedication to her existing position, while also giving a nod to her unique personality and sense of humor.