I have absolutely no experience with custom sticks so I’m submitting this idea with 100% humility. Somebody might have thought of this before and it failed, I don’t know. I know stick players and have seen stick players. When they play with them on their laps, it tends to slide all over the place. At some point I imagined that a person could make a custom stick that had velcro straps coming out of the bottom. Each leg could be strapped individually instead of one loop going around both legs so the stick will remain in place regardless of the player moving their legs closer together.
Well, that’s all I got. If it doesn’t work then I didn’t lose anything by posting. Just thought this might help.