Still catching up with the history. At this point it was the end of April and the beginning of May 2015. My sessions were still centered on deliberate deep breathing and refining muscle movement.
During two sessions, about a half-hour in, I could feel a rush somewhere behind my balls. It was similar to the feeling I get when I start gently stroking my cock head. Nothing too exciting; just a little something. The sensation evaporated and slowly returned, but slightly amplified, similar to the feeling I get when I continue gently stroking. Then it went away and did not return. I relaxed more in hopes of luring it back, but I fell asleep.
Sleep has been a real obstacle for me. Many times I've been focused on relaxing, then realized my ongoing mental narrative had wandered off into dreaming. I don't believe “alert” and “relaxed” should be mutually exclusive states, and I continue to search for the balance between them. Advice would be welcome.
The training material puts special emphasis on not touching your cock during a session. Touching at the end of a session or after a session is fine, but not during. My original interpretation of this advice was that adding penile stimulation risked setting up ejaculation as a conditioned response to rectal stimulation. I wanted to avoid that so badly that I tried to exclude erections. When I felt my cock stiffen, I slowed everything down until it went away.
That was insane. Nobody over twelve years old should mentally speak the words “Go away, boner! You'll get us in trouble!”
It's difficult to know whether the start of erection was causing the warm rush, or if erection was the result of my reactions to it, but the two were linked together somehow. I wanted more of the warm rushes. If they turned out to be pointless sensations, they were still worth studying. I repealed my ban on erections.
I had sessions for another couple of days where nothing especially noteworthy happened, but I was changing around several of the experimental variables. Lube types, positions, condom method, watching porn, fantasizing, etc.
I learned that I don't like high-glycerin lube at all. At one session, I injected a few ml of System JO anal H2O–a style specifically targeted at anal use–and was just about to insert the helix when my rectum cramped up to expel. I had made an effort to ensure I was empty before starting, but I wasn't going to risk shitting the bed on a wager that my ass was calling in a false alarm. A phantom poop ruined the evening. I already disliked the lube for being way too oily, but that was unpleasant at a different magnitude. Awful stuff.
I learned that others have had bad reactions to glycerin, including skin irritation. The lube I was originally using with the MGX )astroglide gel( might have been the real origin of my dissatisfaction with it.
…and the indirect origin of my satisfaction with the helix syn.