Decorate cake. Using ruler and toothpick, divide cake into fifths. Make small marks with toothpick where blue and rose fondant come together.
Using decorating brush, brush back of pleats with piping gel. Attach to cake, covering seam between blue and pink fondant.
Repeat with remaining pleats, overlapping edges of each pleat.
Using fondant roller, roll out medium rose fondant to 1/2 in. thickness. Using “D” cut-out, cut 5 hearts. Attach hearts where pleats meet.