You will need to cut two pieces of fabric 6 inch square and have several 4 inch strips of ribbon. Also cut a 6 inch square of plastic that makes noise when you crumple it.
The plastic shouldn't be able to absorb moisture or it will lose its crinkle and might mold in the toy. I used the plastic from baby wipes refills. Cellophane is great too.
Lay one fabric square right side up and pin ribbon folded in half along edges. Have the folded end facing inward. It actually helps to put the pins on the wrong side of the fabric.
Next lay the other fabric square wrong side up so the two right sides are facing each other. Then place the plastic on top and pin all together.
Like so. I had put my pins all on the same side so they would be easily removable when sewing and wouldn't prick me when turning the square right side out after sewing.
Sew a 1/2 inch seam allowance leaving about 1.5 inches open in the middle of a side (not a corner). Don't forget to backstitch! Trim edges and cut a diagonal on the corners.
Turn right side out and fold in the hem of the opening. Top stitch all the way around.