When leaving the last cave, hold "U" and then press "5" at the exact frame so Guybrush puts the head away. Then walk to the side of the cliff as in the head skip revisited video.

This is faster (but just as hard) than the "traditional" head skip that started by talking to the head at the exact frame instead of using it. The reason is that, when talking to the head, the animation where Guybrush puts the head away after talking to it is one second longer.