New experience... do you know the cause?

For the last couple months I’ve been self locking when my wife isn’t around or when intimacy isn’t going to happen. I’m still working through some cage sizing issues but it’s been enjoyable. Sex is a fairly infrequent affair, often being three to six weeks apart. When we have sex it’s very enjoyable. My wife is very vanilla - we own no toys and when I initially proposed positions beyond me on top or her on top she thought it was a bit kinky. Anyway, three weeks ago we had sex and I decided I was going to try self enforced orgasm denial until the next time we had sex. I’m caged when I can be and using the “honor system” the rest of the time - though I’m only really honoring the promise I made to myself. I’ve stopped looking at porn and I’m not masturbating to orgasm, though I have edged a number of times. Anyway, it’s three weeks today and things are starting to get really interesting. I was uncaged entirely for the last few days due to travel and, when I put it back on today, it was a really intense feeling. I drove across town and the vibrations from the car were enough to make me think I might orgasm in the car. I pulled into a parking lot for a couple minutes and, suddenly I felt like I was going to orgasm. I felt myself grow to the confines of the cage as there was the building feeling I associate with being about to orgasm. Then felt a euphoric high that I’d normally associate with orgasm. It felt amazing and a bit as if I was floating. I felt like I was going to have a bunch of cleanup to do but when I checked, there was no ejaculate that actually came out through the release mechanism. It happened two more times over the next couple hours though to a slightly lesser extent. I thought at first it might be an orgasm with no fluid that managed to get out but, sitting here now, I’m incredibly horny and don’t seem to feel any decrease in libido. In fact, everything feels extra sensitive which is driving me a little nuts. Has anyone else experienced this? It doesn’t seem like a ruin (no ejaculation but lots of pleasure), it clearly wasn’t an involuntary fluid release since there was no fluid, and an orgasm seems unlikely since I didn’t have any of the decrease in desire I’d normally associate with orgasm. So what was that? Thanks, Dan