A little while ago I realized that the line of my index finger from the base of my index finger to the tip of my finger created a nice line and angle for contouring or bronzing. It’s an easy and quick guide. I created an L shape with my index finger and my thumb, the two finger stretched as far apart as they can go. The skin between the thumb and index finger can be right under your bottom lip. The nice thing about this technique is that you can switch hands to do both sides and get the same angle(granted they both can stretch the same or similar amount on both hands).