For smaller wallhangings and minis, I have a 20" square of cardboard that I sprayed with adhesive, then put a 20" piece of white cotton batting onto.
This is a portable, lap sized sort of design board, that not only lets me arrange pieces and pin bits down onto it, but also acts like a pincushion, and holds everything like small scissors and pins and scraps from sliding around while I'm working.
I can use it while watching tv or visiting with friends.
If I need to put it aside to get up and tend to something, I set it on a side table or other surface and it's all still right there when I come back to it.