The ornamental design for a drinkingstrawregulator, as shown and described.
FIG. 1 is a perspective view of a drinking straw regulator, showing my new design in use;
FIG. 2 is a front elevation view thereof, the rear elevation view being a mirror image thereof;
FIG. 3 is a right-side elevation view thereof, the left-side elevation view being a mirror image thereof;
FIG. 4 is a first top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a second top plan view thereof; and,
FIG. 7 is a third top plan view thereof.
The broken lines showing a drinking straw in FIG. 1 depicts environmental subject matter that forms no part of the claimed design, while the remaining broken lines shown in the drawings depict parts of the drinking straw regulator that form no part of the claimed design.