What Makes The Sweet Spot "The Sweet Spot"?

I started thinking about this when contemplating the frequency of sessions.

I used to have a session every night.  I started to find over time the sessions provided me with minimal results.  After reading a lot of posts here, I heard many members say that sessions should not be so frequent.  I did start to have sessions every other day, sometimes as far as 5 days apart.  I did get some high points, but the results I discovered were interesting.

There was always that one night where the session was enough of a breakthrough to where I told myself "it was worth the wait".  But most times... Honestly...  I found the times I waited the most ended up being duds.  My experience has shown every two to three days is ideal, but after spreading things out a bit, going back to everyday every so often still produces consistent results.

Last night I feel as though I had my best session yet.  This was three days between sessions.

I know there is a lot involved here - what you eat, how much sleep you had the night before, fluids, etc.  But I am finding the pressure put on the prostate to be very inconsistent.  You either have something great or sometimes nothing at all.  It really does make me think about the beginning of my journey, where I felt I was getting no pleasure from Aneros.  If the mechanics of the prostate are the same for everyone, shouldn't the cause and effect relatively stay the same?  Meaning...  If my eating, drinking, sleeping, and mood doesn't change, shouldn't I be getting the same pleasure from prostate contact each time?  If not...  What is the secret here?

Does frequency of sessions change the sensitively when stimulating the prostate?  Or is this a mental block to where I can day after day have mind blowing pleasure?

I'm sure some of you can provide charts and graphs to me.  What actually is the mechanism that causes you to get pleasure from prostate contact (biology wise).  Maybe that is a good start...  It can't just be arousal since we are all typically aroused going into sessions.