Plumping Top Coat Plumping Top Coat builds instant volume to plump nails for a gel-like look with a protective, high-gloss finish. OPI Plumping Top Coat can be used over any lacquer shade. It makes nails appear thicker and stronger*, prolongs manicure wear and protects against chipping, prevents nails from yellowing and staining, and provides a gel-like look. Used as the final step in a manicure service to seal in color and extend wear.