I believe I have finally arrived...but only to start a new journey

It happened totally unexpectedly and was not what I expectedbut I expect more and more because it was amazing.

To describe my typical aneros session,
I use a small suction pump to make my nipples plump and engorged
then put a pillow below and lay on my back, knee up and feet down, slowly massaging nipples.
After 10-20 minutes, I'd get some tingling sensations on my bottom half,
subtle twitches on my leg and feet, erection and precum, all the good thing.
Normally, after 40-50 minutes of repeating the building-up and plateau-ing
I get tired of it or time passes too much and I just jack off and finish the session

But today, subtle twitches became more violent and intense shaking
and soon I was breathing heavy and my whole body convulsing for about 10 seconds.
After my body stopped shaking, my lower abdomen still twitching,
I had to have more of this, but then again my body already knew that.
Slowly shaking of the body lasted longer and more violent
to the point where if someone was watching, s/he would've thought I was having a seizure or getting exorcised or something.

This lasted for about 30 minutes and I badly wanted to continue but had to end.

I'm curious as to what will happen next time and eager to find out what my body will deliver.