Decorate bow. Place cookie on cooling grid over parchment paper. Pour thinned red Color Flow icing over cookie. Tap grid lightly to smooth icing and remove air bubbles. Move cookie to parchment paper-covered surface. Let dry until set.
Using full-strength red Color Flow icing and tip 10, cover top of bow, smooth with finger dipped in cornstarch. Use edge of spatula to imprint lines. Overpipe center knot, pat smooth with finger dipped in cornstarch. Let dry until set.