Thats the masonic gesture for "mason in distress" Alternatively, by touching ones own head before giving testimony or using the phrase "is there no help for the widows son" supposedly alerts other masons to their need of help. Throw it in the google machine and check it out. Idk if they have developed new code though since we are talking about these codes and they havent been secret for a while. Another that i have witnessed being used is mentioning being a "traveling man" to cue other masons to your status