Abstract: A method and kit for modifying the strap of a shoulder-supportable bag to reduce slippage of the strap, wherein a strap extends from a first part to a second part of the bag and has a top surface and a bottom surface, a portion of the bottom surface of the strap adapted to rest on a person's shoulder while transporting the bag. The kit consists essentially of: a flexible, pliable, compressible foam rubber member, the foam rubber member having a maximum width less than or equal to the width of the strap and a length equal to or greater than the length of the portion of the bottom surface of the strap adapted to rest on a person's shoulder while transporting the bag; and, an adhesive member, the adhesive member adapted to fasten the foam rubber member to the strap, having a maximum width less than or equal to the width of the strap and a length equal to or less than the length of the foam rubber member.