I know not all people use humour in this way, but I’ve found some solace in inside jokes with my aphantasia with my friends personally.
For example, I like to joke that my mind is like an etch-a-sketch. I just crack my neck, and let the “image” in my head dissolve like shaking an etch-a-sketch into nothingness.
Another example is a friend saying “imagine [x]”, and I just reply with a flat, deadpan “no”.
A final example for me is calling my own brain “The Cave of the Present”. This is the name of an area in a video game called EarthBound, as I am forcibly in the present with my aphantasia. And caves are typically dark lol
I’d love to hear any inside jokes you guys have!