Tomlinson prefers using a mitt due to the bigger surface area. When applying tanning water, however, she uses a brush because it's less messy — making the point that your applicator of choice really does matter.
She explains that it's worth spending the extra time blending everything together to ensure perfect, even coverage and no dreaded streaks. For her foundation-plus-tanning-drops base, Tomlinson applies the mixture with a brush first, then ensures everything is evenly distributed by going back in with a Beautyblender.