The ornamental design for a crutchcushion, as shown.
FIG. 1 is a top view of the crutch cushion;
FIG. 2 is a underside view of the underside of the crutch cushion;
FIG. 3 is a plan view of the end side of the crutch cushion; and,
FIG. 4 is a plan view of the elongated side of the crutch cushion in use,
the dotted line shown of a crutch is for illustrative purposes only and
forms no part of the claimed design.