FIG. 1 is a perspective view of a first embodiment of a mask cushion showing our design;

FIG. 2 is a rear view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a perspective view of a second embodiment of a mask cushion thereof;

FIG. 6 is a rear view thereof;

FIG. 7 is a top view thereof;

FIG. 8 is a bottom view thereof; and,

FIG. 9 is a front view thereof.

Where included, broken lines showing environment or structure are for illustrative purposes only and form no part of the claimed design. Where included, dotted lines represent the border between claimed and non-claimed subject matter and form no part of the claimed design.

The use of stippling is used to indicate shading.