Pad stitches are a type of running stitch made by placing small stitches perpendicular to the line of stitching. Pad stitches secure two or more layers of fabric together and give the layers more firmness; smaller and denser stitches create more firmness. They may also be used to enforce an overall curvature of the layers.
Tailors pad stitch a jacket's lapel and undercollar to give them more firmness and to help them maintain their curvature. The line of stitching usually runs parallel the direction of the most important curve of the layers. For example, pad stitches in a suit's lapel run parallel to the lapel's roll line; pad stitches in the undercollar of a tailored jacket run parallel to the collar's back edge. (source: Wikipedia)
Here is a diagram of a pad stitch by Scott Perkins of "Garb for Guys":
Scott offers some excellent information on pad stitching on his blog; how to use it, where to put it, and why. Check it out.
Here is an excellent video on pad stitching the lapel
Have you tried pad stitching? If you have, share with us below, where you used it and the outcome.