This sit-upon fits into a kid's pocket, ready to fill with grasses and leaves whenever a soft place to sit is needed.
Place one bandana on top of the other and stitch them together on three sides. On the open side, attach a Velcro tab to make a simple closure (experienced sewers might like to make a basic button-and-hole closure instead).
To fill the pillow, gather the softest grasses, dead leaves and moss you can find, carefully broken into pieces small enough that they won't pierce the fabric. No woods nearby? Backyard grass clippings (preferably dried) work well.
At day's end, just shake out the filling and fold up the sit-upon for the next day's adventures.