See if you can rubber band it somehow so it won't slip. Wrap it around the bar so that it won't go farther into the foot, then wrap the rest around the top of the foot so that it won't slip the other way. Or if the bar goes all the way thru, you can loop on one end and over to the other, and that way it won't move. Hope you can understand what I am describing. Sometimes things get lost in the translation.