The ornamental design for a drinkingmug, as shown and described.
FIG. 1 is a perspective view showing a drinking mug according to my new design.
FIG. 2 is a top view thereof.
FIG. 3 is a side view thereof.
FIG. 4 is a bottom view of the drinking mug of FIG. 1, the drinking mug having a first insert received in a bottom of the mug.
FIG. 5 is a bottom perspective view thereof; and,
FIG. 6 is a bottom perspective view of a second embodiment of the drinking mug of FIG. 1, the drinking mug having an alternative second insert received in the bottom of the mug.
The portions of the drawings appearing in broken line do not form a part of the design.