If you’ve got an Apple Pencil and you find it too slippery, and the tip too crayon-like for your tastes, here industrial designer Eric Strebel shows you how he fixed both issues.
In the video he touches on a subject familiar to prototypers, where you often have to make a thing to help you make the other thing; he also leaves in some stuff going wrong on camera, so you can learn from it. (I always find that stuff incredibly helpful, as I feel like half of my time in my own shop is spent on fixing my own mistakes.)
https://www.core77.com/posts/99282/How-to-Modify-Your-Apple-Pencil-to-Have-a-Glossy-but-Grippy-Texture-and-a-Sharper-Tip-for-More-Accurate-Sketching