I read a great book on Buddhism. It was a series of talks, transcribed and edited liberally.
One chapter was Black Pearl Meditation. I gained the sense it is a teaching passed on to their student maybe twenty years of meditation practise. 'Reflections on a Mountain Lake' is the name of edited transcriptions. I was practising it today and noticed a great physical reaction as I visualised the in and the out and the cracking. I sat up straight spontaneously and realised I was physically responding to the process. I have lent my copy to my Auntie. And since her returning it, I have given it to a neighbour for keeps. It's great. It teaches that us newagers had it a little wrong. I incorporate it occasionally.