This example of Bill Shatner touching his own hair is from the final Star Trek episode "Turnabout Intruder". It is almost identical to the moves illustrated in our previous post, in which Shats describes this particular performance.
As a last episode "Turnabout Intruder" is far from good, but as a stand-alone episode, we think it's thoroughly entertaining and Shats gives a great performance as an evil woman.
On a related note - a reader has mentioned a toup scratching moment in a documentary on the DVD release of the movie Free Enterprise. We don't have this in our toupology archives, so if anyone has and can post the clip somewhere, we'd be very grateful!