1Heat oven to 350°F (325°F for dark or nonstick pans). Make, bake and cool cake as directed on box for two 8-inch or 9-inch rounds.
2Reserve 1 cup frosting for decorating. Place 1 cake layer, rounded side down, on serving plate. Spread with about 1/3 cup frosting. Place other layer, rounded side up, on top. Frost side and top of cake with remaining frosting. Make vertical lines on side of cake with decorating comb or tines of fork if desired.
3Tint 2/3 cup of the reserved frosting pink with 1 or 2 drops red food color. Place pink frosting in decorating bag with small writing tip #2. Pipe 2 circles around outer top edge of cake, about 1 inch apart, leaving 3-inch opening at top. Make loop design within circles.
4Tint remaining 1/3 cup frosting blue with 1 or 2 drops blue food color. Place blue frosting in decorating bag with writing tip #5; pipe outer border of bib. Pipe inner opening of bib about 3 inches in diameter; join circles with tie at top. Make small bows on bib and write desired message in bib opening. Pipe dots between bows with remaining pink frosting if desired. Store loosely covered.