The ornamental design for a self-retaining communication device, as shown and described.
FIG. 1 is an isometric view of a self-retaining communication device showing our new design, the opposite interior of the ear cup is a mirror image of the interior of the ear cup that is shown.
FIG. 2 is a top plan view thereof.
FIG. 3 is a bottom plan view thereof.
FIG. 4 is a right side elevation view thereof.
FIG. 5 is a left side elevation view thereof.
FIG. 6 is a rear elevation view thereof; and,
FIG. 7 is a front elevation view thereof.
The broken lines in FIGS. 1-7 depict a portion of the device that forms no part of the claimed design.