I have been employing the Mike Weir/Anthony Kim waggle for my irons.
I was trying to feel PP4 and just couldnt do it with the sleeve/glove in my armpit drill so I did that once piece takeaway waggle and initiated with muscles in my left armpit.
Lo and behold it worked!
I find really curious that all the PP are located on the shaft and more or less in the AFT position except for PP4(left armpit) so it really a pressure point?