I’ve been working on that shower juggle pattern for a year now. Progress is slow but a couple of days ago, I noticed it got better when I held my arms pretty rigidly within the pane of glass. You can still tell I tend to morph between a half shower and a full shower. It’s also called a circle juggle because that’s sort of what it looks like.
I think the Svengoolie T-shirt gives me good luck.