I saw this on the internet and thought it would be great to have one. It's one of those 
wooden TV trays (I found these at garage sales) and drilled 2 holes 
in the top for ventilations and put 4 layers of warm and natural and then the 
silver fabric they use for ironing board covers. 
I stapled it all on the underside. This works great. When I don't need it, it folds up.
I plan to make a covering for it out of cotton with a drawstring to keep 
the silver fabric clean and the covering can be taken off and washed.