Status report after 10 months with the Aneros

Hi. I've now been using the Aneros for 10 months... and about 1-3 sessions per week.
I own the Maximus, Helix and Progasm (purchased in that order). I use mostly the Helix and the Maximus because the Progasm seems to be too big.
There has definitely been some progress since I bought the first Aneros, but I have not experienced any prostate orgasm yet. Only good feelings in general... and hard erections etc. The only position that works for me though is laying on my side with both legs pulled towards the stomach (about 90 degrees).
In that position I get these "buzzing" sensations, like blood is streaming to the prostate area.

In the recent 2 months I've experienced some involuntary "quivering" in the prostate when I hold the contraction for a few seconds. With that I mean flexing the PC muscle and hold it, so the aneros is pressing on the prostate.
Is this quivering a so-called "involuntary contraction"? Or is involuntary contractions = involuntary flexing of the PC muscle?
What might the next milestone in my "journey" be?