I had a even better session last night. 
My butt was craving all day after my last post so I saddled up again. 
Got to dry O zone again and rode that for a hour or so. 
I think it was about 2 hours in and I started to get in a frenzy and I could feel a massive build up of energy starting. 
It got greater and greater until I was almost about to explode some how but I dont know how. 
Alas the expectations or something got in the way and it subsided :) 
I did not giveup but instead of the build up I couped something different. 
I have never read about it before either. 
I had a start of a build up like before but only slight and then the aneros dug itself in hard and clicked into place like what I call a dry O and then like the ejaculation felling of the dry O or a kegal thrust I went into some sort of spasm. 
My body started spasming like a kegal at around 2 thrusts a second. Just the PC muscle. 
It kept going like this constantly for I estimate 3 or so minutes! 
Every now and then I might miss a thrust but it just kept going? 
There was pleasure but a lot of energy was beeing put into it at the same time. There was a feeling of it building my arousal but not to anything huge. 
After the 3 minutes or so it stopped and just went back to anal twitching. 
I was buggered and went to sleep. Woke a few times through the night with miss helix teasing me a bit. 
In the morning I removed it for a pee and then reinserted but with the eupho instead and had a few dry Os and then decided to call it quits. 
I was so horny still I decided to have a super T. 
It was a massive build up and as I came I squeezed so hard The eupho shot out half a meter away from my arse onto the bed! :( 
It was a bigger load of cum than usual.