The ornamental design for a self-massaging device, as shown and described.
FIG. 1 is a top front perspective view of a self-massaging device;
FIG. 2 is a right elevation view thereof;
FIG. 3 is a left elevation view thereof;
FIG. 4 is a top plan view thereof, the bottom plan view being a mirror image thereof;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a rear elevation view thereof; and,
FIG. 7 is a perspective view thereof, shown in use.
The broken lines shown in the drawings illustrate portions of the self-massaging device that form no part of the claimed design.
The cutaway symbols illustrated in break lines in the drawings indicate a symbolic break in the length of the design for the self-massaging device indicating an indeterminate length. The appearance of any portion of the article between the break lines forms no part of the claimed design.