The ornamental design for a hairfrostingcap, as shown and described.
FIG. 1 is a top front perspective view of a hair frosting cap showing my
new design in use; the broken line showing of the human form in FIGS. 1
and 2 being for illustrative purposes only, and forming no part of the
claimed design; and,
FIG. 2 is a rear elevational view thereof.
The cap is bilaterally symmetrical; and the undisclosed interior of the cap
is unornamented.