Few questions

Hey been using aneros again after a few years(stopped as had no feelings), trying again with a progasm and with a different mindset.
I have found that using it in the bath in silence with my head under the water has given hopefully some results.
After ten mins or so of totally relaxing I start to clench both muscles starting softly until after another ten mins I’m clenching as hard as I can and start to feel my heart beat strongly and it moves down to either my prostate or close by, is this a sign I’m on the right track?
Also when people talk about involuntaries does yhat mean the muscles are clenching on their own or what I’m finding that when I’m holding a contraction it’s pulsing?
Any help or advise would be amazing !!!