Hi Charles!
Well, you,have seen the back of my vehicle in its untidy state..you may have spied my mats
Imuse a piece of Astroturf "underlay" doubled over and held together with gaffer tape.,it,is very flexible and waterproof.i also use a piece of heat reflective backing from underneath a laminate floor for putting on delicate surfaces. All,of these are a similar material,to,the kids playmats above