I loved this idea from HighOnDIY site!
i think i'll give it a try. ;)

Here’s what you will need:

Step 1: Remove the cover from the pillow and lay it flat with the front of the pillow cover facing up. If the cover is not made of a thick fabric, place a magazine or cardboard inside the cover so the mixture doesn’t seep from the front to the back of the cover.
Step 2: With a pencil, draw a heart in one of the corners of the pillow cover. Make it the size you like but make sure to leave space for the sprinkled glitter effect.
Step 3: To create the glitter mixture, add one part glitter to two parts Mod Podge in the container and stir thoroughly with a brush.
Step 4: Using the same brush, paint the heart with the first coat of mixture. Don’t worry about making a crisp and defined heart shape. You can let it bleed outside the drawn shape since we are going for the gradient/sprinkled effect. Let the first coat dry for 10-15 minutes and add 3-4 more coats while letting each one dry before applying the next.
Step 5: Take the second brush and dab a tiny bit of the mixture on it. Flick the brush on the cover making sure to sprinkle the mixture off the brush to the cover instead of splattering. Concentrate the sprinkles closer to the heart shape and repeat as necessary.
There you have your sparkly pillow cover! Let it dry overnight before putting it back on the pillow.