Weird orgasm - any ideas?

I'm still quite a new user. Everything on here I read and have been told involves relaxation, so today instead of using leg tension to help bring on an orgasm (it works for me) I decided to totally relax.
Difficult at first and took a while to bring on any sensations, but eventually it grew and I had a very unusual orgasm. Up until now each one has been mind blowing with intense pleasure and lasted 5-20 minutes. This time I sort of drifted into the orgasm more slowly and felt everything happen in my pelvis as usual but almost no pleasure at all, just the sensation of having a release of pressure, no ejaculation, and no spasms, definitely some sort of orgasm and it only lasted 1 minute maximum. After I felt unusually refreshed, after a normal prostate orgasm I actually just want to do it again but this time I feel totally satisfied. All very odd.

Since starting using the aneros, and having plenty of prostate orgasms without it as well, I have had a sort of tension and trembling in my pelvis and lower abdomen as if I really need another orgasm. That has gone (for now at least). I feel like I have done something good, but not sure what.

Could have just been a dud session I suppose, or maybe I did actually 'unblock' something, looking forward to my next session to see if anything has changed. I would be fascinated if anyone else has experienced this sort of thing.