Mac Lip Prep and Prime. To get the best results it is always worth investing in a good lip primer and this is one of the very best. A colour-free base to wear under lipstick. Adds light moisture, smoothes and refines the lips to perfection. Improves the appearance of applied lip products as well as their longevity. Easy to apply to the lip area, this product also helps to apply your lip liner as the pencils simply glide along with little to no pressure.