Try this out, I have been meaning to put this on line for ages but forgot.
Step 1: Rustle up
1 - One length of old bike inner tube - about 14 inches long - cut to final size when your all done.
1 - One length of inner tube about 1 inch long.
A pair of scissors to cut the material.
Step 2: Get A Grip
Step 3: Next
Step 4: After That
Your done - adjust for what will be a really comfy fit ( you'll see ), and cut to the finished length.