Hi Nightwalker, I've just read through your journal for the first time and really enjoyed it.
I went through a phase of having brow centre strobes, which,yes scares the heck out of you before you find out what they are,but mine were followed by an explosion in the head .Felt the whole body jumped but it didn't even move.
Around this time I was concentrating a lot on the brow using the bouncing the ball through the head ( NEWS) and once or twice had a headache with it. Was advised my CFT to lay off a bit if headache follows. But that was me not you!
Still I haven't answered your question about the click as mine was an explosion,sure someone here will know.
I have noticed that Robert Munroe uses the term "CLICK" a lot in his Far Journeys book and explains that when we read Click he means Instantaneous change in consciousness,but I don't know if he uses the term because that was what he heard.