You will need two colour polishes and a top coat, then a sponge, a plastic sheet and toothpicks.
Using the lightest of the two colours, paint your nails and wait for it to dry completely
On a flat surface, paint a generous amount of the colours right next to each other on to the plastic. Make sure they’re just about touching at the edges
Using a toothpick, swirl the two colours together where they meet. The area where they mix will determine the length of the graduation. So if you want a long graduation, mix a bigger section of the colours, if you want less of a fade, just mix them together a tiny bit
Take your sponge and dab it directly down on to the polish a few times
Dab the sponge directly down on to your nail. Keep dabbing lightly and moving it very slightly up and down your nail
You can repeat this step as many times as you need to. Just make sure each layer is completely dry before sponging again
Add a topcoat. Or two or three! The sponging makes this mani very bumpy so you may need a couple of topcoats just to even out the surface