Spread or pipe vanilla frosting over cupcakes. Sprinkle with multicolor confetti sprinkles. Tint remaining white frosting various colors (such as pink, lavender, and primary colors) with paste food colorings. Place different colors of frostings in separate heavy resealable plastic bags. Snip off a very small piece from one corner of each bag. Pipe strands of the colored frostings over cupcakes and serving plate to look like streamers.