Twitching???? Am I on the right track?

After several months of . . . nothing, I resolved myself to keep working at it until I at least felt something. Here's what happened last night:

Model: MGX
Lube: KY jell, applied inside, via eye dropper
Position: On back, right knee bent with right foot on bed, left leg crossed, with left ankle resting on right knee
Activity: Basic in and out movement

What happened: After approximately 30-45 minutes of repetitive in and out movements, I knew I was massaging my prostate because I could feel a definite, firm nudge on each intake stroke, and I was leaking small amounts of prostate fluid. At one point, I even had a semi-erection.

I decided to pursue this further, and soon I noticed that, at the conclusion of each outward stroke, I definitely felt what I'd describe as a slight "tap," almost like an echoing response to what I was doing. I imagined it sorta like a movie scene of a mine cave-in, with the trapped miners tapping the walls in response to what they were hearing, sorta saying, "Here I am."

So, here are some things I'm wondering: Am I actually getting somewhere? Is this sort of "tapping" response a "normal" response? Could the tapping feeling have been something going on internally in my body, or am I mistaken and it was just caused by a ridge on the MGX as it moved in and out?

Bottom line: It was a good feeling, and I'd like to feel it again and more intensely. But, I'm looking for some verification, please.

Thanks.