This is something between a question and a shower thought. People use air quotes to stimulate “quoting” a word or short phrase in the middle of a sentence. Are there any other punctuation marks that can be stimulated this way? And in particular, is there a gesture for parentheses (like this)?
If not, then why not? How did quotes get special treatment?
And if yes - how many people would actually understand what those other gestures mean? (I am reminded of that scene from Friends where Joey admits he doesn’t know what air quotes mean)
Image taken from Wikipedia: https://en.wikipedia.org/wiki/Air_quotes / https://commons.wikimedia.org/wiki/File:Airquotes.gif
It’s a bit theatrical, but the closest thing feels like cupping a hand to the side of your mouth like you’re saying something sotto voce. It only really works if you have a reason to downplay what you’re saying rather than just any random aside though.
For body language more generally, you could just take a half step to the side with a bit of a head tilt or wave of the hand (feels more natural for something like a monologue though).
I like it!