I recommend a spatula.

This is the Picasso Two-Way Makeup Spatula~ It is shorter and smaller than standard spatulas, so I am using it very well because I can apply it delicately to both wide and narrow areas! I am also extremely satisfied because I can pick up cushion foundation and apply it thinly with the spatula! The back part is designed to scoop out cream, so it can be used for skincare as well!