Summarize this article in one sentence.
Many people use a Beauty Blender, or a generic version of this well-known makeup sponge, to apply their liquid foundation. To use this sponge properly, you’re supposed to dampen it before applying makeup. Instead of using water, you can use setting spray to dampen the sponge.  This may not work with all sponges. Some brands may deteriorate from a setting spray, so be careful. The moisture on the sponge will help blend and smooth the foundation easily and evenly. The setting spray will also help prevent the foundation from coming off over the course of a long day. Many powder eye shadows go on very lightly, and it seems like you have to pack on multiple coats to get the bold, pigmented color you want. Setting spray can help with this. Take your shadow brush and dip it into the powder eye shadow you will be applying. Then, before you apply it to your lid, spray the brush with your setting spray. This will make the shadow more opaque and bold than the dry powder alone.  The eye shadow will be damp going onto your lid, but it will dry quickly. The setting spray will help your eye shadow stay in place and last all day, without smudging or creasing. If you're trying a new look or doing a look that requires blending, avoid doing this. Wait until you have completed your look, then close your eyes and spray them. To cover dark circles and make your eyes appear brighter, apply concealer under your eyes. Use your finger to dab a few dots of the product. Then, spray your concealer brush with setting spray before using it to blend in your concealer.  By getting your concealer brush damp with the setting spray, you will make it easier to blend the concealer. The setting spray will hydrate the delicate skin under your eyes, and it will also keep the concealer looking smooth and flawless, rather than splotchy or crease.

Summary:
Use it to dampen your foundation sponge. Spray it on your eye shadow brush. Spritz your under-eye concealer brush.