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.