A simple project from the days of Girl Scout Camping.
What you need
Felt back table cloth
Plastic baler twine or Duct tape
*Fold the table cloth double so when you cut it you have matching pieces
*Cut the table cloth into squares big enough to sit on .. it really is just a personal preference how big you make these.
*Lay folded or unfolded newspaper between the double cut section of table cloth (how much newspaper you use will be determined by how much padding you prefer when sitting on the ground)
*Fold over the edges of the table cloth square and duct tape them down, seling the newspaper padding inside.
*If you use the plastic baler twine, you will need to hole punch rows across the outter edge of the table cloth square so you can follow it with a single stitch weaving the twine in & out until you get back to your starting point.
*There are a lot of ways to put personal touches on a situpon, and may different ways to make them .. from changing up the padding you use for the inside to decorating the outside with permanent markers, stencils, foam cut-outs, or making handles on two ends so you can carry it easily.