Using an electric mixer, beat the egg whites and cream of tartar on medium-high speed until foamy, about 1 minute.
Reduce the speed to low and gradually add the sugar, beating until just incorporated. Increase the speed to high and beat until medium-stiff glossy peaks form, 5 to 7 minutes.
Separate into bowls and tint different colors. Transfer ? of each color to separate pastry bags fitted with fine tips. Use a few drops of water to thin the icing remaining in the bowls for flooding; place in separate resealable bags; snip of the corners.
Using the thicker icing, outline lovebug wings on the cupcakes, then flood using the thinner icing. Decorate while the icing is still wet. For multiple colors, let each icing dry before applying another.