Try using your hands for me that is the best way to blend it out and apply little by little. But yes the warmth of your hands works the best I would not use a sponge of any kind because the product will get absorbed to much. Hope it helps
My fav way to apply this is with my fingers. I feel the warmth of your fingers helps this foundation apply a bit smoothr.I have also tried beauty blender and sigma brushes to apply and still think my fingers is the best way. Hope this helps.