A flexible sleeve includes a first flexible sheet of a first hardness. The first flexible sheet has a first perimeter including a first lip edge and a first pocket edge. The flexible sleeve also includes a second flexible sheet of a second hardness, different than the first hardness. The second flexible sheet has a second perimeter including a second lip edge and a second pocket edge. The second pocket edge is joined to the first pocket edge, and the second lip edge is free from the first lip edge so that the first flexible sheet and the second flexible sheet collectively form a pocket having a mouth defined by the first lip edge and the second lip edge. The flexible sleeve further includes a connector joined to the mouth and configured to mate the mouth to a head of a device while the pocket substantially covers a tail of the device.