Yeah, My xDeep wings came with some silly little knob that made me have to think too much.
I shortened the pull string and put a larger knob on it. I trained some more last month and shortened the string even more.
You can take an old die (singular of dice) and drill a hole in it for the string to pass through. You might mistakenly project the lame image of a Vegas gambling lizard but it will be hard for the fingers to mistake a square knob.
There’s also a solution from DGX (the one I use).
DGX Large Zipper Pull