How long before shaking starts?

I’ve been using my helix syn on and off for a couple months now and think I’ve been making progress. I’ve checked out things like the prostate orgasm info graphic chart thing, but I can’t seem to get to the part where my body starts to shake. I’ve gotten involuntaries, had some warm and pleasurable feelings in my prostate that build up to a point where it’s like my prostate goes numb ,but can’t get past it. How long do you usually go in your sessions and how long does it usually take in a session to get to the shaking? Also how long did it take until you first had shaking begin?