What is happening here?

This is happening more or less every session I have. I am using an aneros device i start a session and withing seconds i can feel the prostate and muscles moving and pleasure is starting to form.

Within 1-2 mins max i am having a full blown super O, or at least a VERY nice dry orgasm. I had one today that might have been the best ive ever had in fact!

That is all great of course and have no complaints. But my issue is that once I have had that one orgasm, it all ends. Stops.

Sometimes there is a build up and a feeling of something happening again, but it just tales off into nothing. I have tried changing positions, nothing works. I think perhaps i need to find a few more that work? not sure.

Buts its almost like im having a refractory period just like with traidtional ejaculatory orgasms!

Do I need to just wait a lot longer and not fall alseep, perhaps my body needs more time to build the next one? (i suspect its this to be honest)
But has anyone else experienced this?