The ornamental design for a pantsassistingdevice, as shown and described.
FIG. 1 is a front perspective view of a pants assisting device showing my new design;
FIG. 2 is a front view of a pants assisting device;
FIG. 3 is a back view of a pants assisting device;
FIG. 4 is a bottom view of a pants assisting device;
FIG. 5 is a top view of a pants assisting device;
FIG. 6 is a right side view of a pants assisting device; and,
FIG. 7 is a perspective view of a pants assisting shown in a position of use with unclaimed subject matter in broken lines.
Left side views not shown are mirror images of right side views. The broken lines illustrating a pair of pants depict environmental subject matter that forms no part of the claimed design.