Hi Still Thinking - I partook of the emblems while in the WTS organization - began partaking in 1989 but actually realized I needed to do so a couple years prior. In fact I received my witness in the early 80's but it took me a long time "to get it" - to comprehend that I should indeed partake of the emblems. I did not go about asking anyone else any questions on the matter - I knew they would think I had lost my mind so just kept it to myself and my conversations with Jehovah in prayer. And He kept prodding me along.
As far as your wanting to know how one determines such a thing I understand your curiosity. In conversation with others that have partaken they often share their stories and I know one sister who even has made it her hobby to go about collecting these experiences. It seems no two of them have the exact same experience and last I heard she had gathered about 40 some (and no that sister is not me) - I have never met anyone else that had the experience I had in person though I saw reference to such in one old WT article - a first person story of an old brother in Germany - but without my experience one would not have realized he was revealing the fact he too was anointed.
So even though it all sounds very mysterious and difficult to explain these individuals have each come to the conclusion they are supposed to partake of the emblems in their own unique ways. If I were to list all the various ways I have heard the first impression would be to just discount them and consider each of the inviduals as "mad, mentally deranged, or odd" but in most if not all the cases I know of, none of the individuals were searching or desiring to be of the heavenly class - All that I knew including myself felt quite unworthy of such a position and lacked any comprehension of "why me?" The experiences included things like "just a sudden overwhelming consciousness - a spiritual awakening that quickened their mind to realization of the need to partake," or another expressed the fact that they had heard a sudden whoshing sound in their ears and they suddenly knew - think I heard of a couple of people that had that experience, and a couple more had this experience of being in a dark tunnel and coming out into the light at the end of it - almost like a near-death experience, one guy's wife was told in a dream or something, one had an experience of a vision - a large eagle appeared to them so real they tried to wake up their mate to see it too but the mate just wouldn't waken so they decided to get up and walk over to it and touch it - no fear involved apparently, but when they started to do so it just faded, another saw a figure of a man holding a baby lamb - and this overwhelming conviction of God's love came upon them plus an amazing array, flashback style of all their sins that had been forgiven, others said a certain scripture just popped out at them like the ones in Chapter 8 of Romans, and so forth and so forth. Some had the strange experience of other people asking them - a series of people in a short time period - if they were of the heavenly group without any logical reasons for the question, and one had a sister make a big point in the Book Study Group discussion that it was sinful not to partake if one had been called when she had no cognizance whatsoever that there was indeed someone present that had been called but who had not yet proclaimed their calling. You may ridicule these things if you like but I would advise against it. I believe they were manifestations of Holy Spirit. No one described seeing a tongue of fire over their heads like described in the Book of Acts, however.
But your next question - wondering how they felt when they left the WTS and discovered they were no longer one - makes an assumption that just doesn't seem to hold true - at least not for myself. I do not believe this calling is limited to just the WTS anymore than I believe my salvation is dependent upon being part of the WTS or that it plays the mediator role for mankind today. I still partake of the emblems but not at the Kingdom Hall obviously since I have become formally disassociated. But it does bring up some important questions to which I do not have answers - if the anointing were restricted to only 144,000 individuals that class would have had to be filled way back in the first century. There is just no way there have been only 144,000 spirit begotten Christians up until now - no way. And although at the time I was within the WTS I believed in the two classes - the heavenly and earthly - and thought it very logical - in fact I still believe there will be earthly members of the Kingdom - it now appears to me the invitation to partake of the emblems is actually open to all believers and there should not be a division being made such as is being done in the WTS. That it is actually a disrespect to the emblems to just pass them around and forbid most to partake. I guess in truth no one is forbidden but the implications and social pressures are such that the great majority do not partake. But I did not come to this opinion until after leaving the WTS so that was not what influenced my decision to partake. Since in truth it makes no difference whether one is or is not of the heavenly class in everyday matters for the WTS I really see no reason they stay with that procedure and believe they are in error to do so. They are creating "class distinctions" among themselves for so doing. The only place I know of that it makes any difference is it is considered necessary to serve on their GB and probably a personal question of the individuals being selected or considered would serve their purposes just as well.
The Scripture Ephesians 4:4-6 comes to mind - One body there is, and one spirit, even as you were called IN THE ONE HOPE to which you were called, one Lord, one faith, one baptism, one God and Father of all persons, who is over all and through all and in all. Notice it says ONE HOPE - the WTS has created two hopes and in so doing they have also denied a large portion of the scriptures from their flock by making them feel it doesn't apply to them. This is serious business and wrong. What God determines He wishes my place to be will always be satisfactory to me - I do not have to be in the TOP ECHELON - where He places me will bring me happiness. Of that I am convinced and whatever He decides will be the right decision - so if you feel I am not of the 144,000 you may be quite right - at this point I simply leave that matter up to Him. He is the One who really knows and the only One who needs to know.
