The ornamental design for a hair-waving headband, as shown and described.
FIG. 1 is a front perspective view of a hair-waving headband, showing my new design;
FIG. 2 is a right-side elevation view thereof;
FIG. 3 is a left-side elevation view thereof;
FIG. 4 is a front elevation view thereof;
FIG. 5 is a rear elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines shown in FIGS. 2 through 7 depict portions of the hair-waving headband that form no part of the claimed design, while the additional broken lines shown in FIG. 1 depict environmental subject matter that forms no part of the claimed design.