This is the mainstay of some conservative treatments used by podiatrists to off load painful areas on the foot and toes. The felt is cut to shape so as not to cover the painful area, but be thicker besides and behind the painful area. The painful area could be a corn or callus or something more serious like a foot ulcer. The podiatry felt padding is stuck on the foot was it usually has a self adhesive backing. This video explains how you can use podiatry felt to help self treat a painful area on your foot: