The ornamental design for a waterbottlegrip, as shown and described.
FIG. 1 is a perspective view of a water bottle grip;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right-side elevational view thereof;
FIG. 5 is a left-side elevational view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a front view thereof attached to a water bottle.
The broken line showing of a water bottle in FIG. 8 is for the purpose of illustrating environmental structure and forms no part of the claimed design.