Tarp skins basically make for an easy way to either take down (by sliding the tarp into them) or move a tarp out of the way. You can get skins made from a solid material (like nylon) or mesh. I prefer the mesh because you can stow a wet tarp and it will actually do a pretty good job of drip-drying.
Do a web search on mesh tarp storage sleeves from mountain goat gear, you'll see some good pics. I am sure others on the forums here can post some pics as well.
Also, check snake-skins on YouTube too, Hennessy has a few videos where he shows how to use them.