WHAT just happened? Nothing but kegel exercise... first time!

New here, decided to say hi!
I'm Nick, 26 yo male. I'm not really educated on the subject of this site but am looking into it so bare with me lol, I just NEED to talk to someone about my experience! May as well get straight into it lol. I have a lack of sensitivity regarding sexual pleasure. I have no problems maintaining an erection, however I last for at least an hour and not by choice. Sometimes I can't even finish vaginally because I run out of steam before I climax. So, I looked into increasing sensitivity and found out that Kegel exercises may help so I've been doing them whenever I remember etc.

So... yesterday I'm at the beach in my own little quiet spot working on my tan, enjoying the sun's warmth. I am just wearing board shorts rolled up. I am completely relaxed and decide to start doing kegel exercises. After just 3 reps I feel something strange suddenly rising up from my groin into my abdomen. I can only explain it as an explosion of electrical fireworks. My core muscles started involuntarily quivering and I instantly gained a rock hard erection faster then ever before. It was intense, and felt like I was about to cum really hard, remember this was after just 3 reps. It felt absolutely unreal however I simply couldn't mentally concentrate on continuing reps and it's like my mind drifted into my erection and everything vanished, it just left me lying there with a boner wondering what the hell just happened lol. I thought it would be an inappropriate place to try and get off at the beach so I left. On the way home it was like I had just been given a massive shot of adrenaline. My hands were shaking and my heart rate was through the roof for an hour after, and I just felt like I was on mdma or something lol I emotionally felt so damn good about everything. Unfortunately I haven't been able to repeat the experience. I think I'm just not relaxed enough.

So first of all... what the hell was that. A P wave? Or a lead up to a Super O even? I don't know and would like your interpretations!
Second... is this normal with nothing but Kegel exercises and nothing else with so little experience? Will this escalate with practice?
Third... will an Aneros product help out with this? I can count on one hand the amount of times I've had a finger in my bum fooling around lol It felt highly uncomfortable physically to get in but once in each time it helped me get over the edge sooner which is sometimes a relief for whoever I'm with lol.

So thanks for reading my wall of text lol, I hope to hear some more educated perspectives and some stories too!