I can't take credit for this idea. I read it on an online message board but it was too good and easy not to try.
First, buy 1 or 2 pool noodles for each bed you will use it on.
Next place the pool noodle under the fitted sheet just at the edge of the mattress.
After the bed is all made it makes a really simple bed rail so your child won't roll off the bed. We set the fold out bed in our cabin against the wall so we only needed one noodle.
I don't have pictures of the other use because the explanation is the same. If you co sleep use the noodle in your bed (at home or traveling) so you don't have to worry about the baby rolling off the edge. Also for an infant, this is great to have in the trunk of your car. You would only need half a noodle or two halves. Keep them there and when you stop by a friends or a relatives and need to give your infant a nap you can make a safe little space so they won't roll off the bed and you don't have to haul the pack and play to those short day trips.***NOTE: If you are putting a child under the age of 1 on a bed please keep the area clear of blankets and pillows. Using the noodles as a bed rail can leave a place for a baby to suffocate if there is too much fabric. Check on your baby regularly if you do this. ( I realized after posting that since this is public there usually needs to be these disclaimers for those of us that may need them.)