Like most people who try the Aneros I was a bit skeptical about the claims of super orgasms and such. This was before I tried it - and I am now a believer.
Typically what I do after I lube it up and insert it into my anus are about 30 of what I call "crunches" - inhale and simultaneously tighten the PC muscle, and hold it for as long as I can. As this progresses I can feel something happening, and the pre-cum really gets oozing about halfway through even though my penis is flaccid. When I'm done with the "crunches" I'll just sort of tighten and relax my PC muscle while I'm playing with another part of my body - my nipples usually, although playing with my testicles feels really good at this time as well. I can usually get a couple of orgasms that way, with my penis still flaccid and no semen, just a lot of pre-cum. After this I REALLY need to masturbate so I lube up and get hard. This is when the intense and constant orgasm starts for me - I think that as I'm masturbating my PC muscle is constantly tightened and this pushes the Aneros into my prostate. The state of orgasm is unbelievable - I shake, moan very loudly, my toes curl up, and sweat like I've been working out for an hour. I usually don't have a penile orgasm at this point since I try to "edge" while I'm doing this.
After a while it almost gets too intense, so I often need to take it out of my anus and masturbate to a penile orgasm. I have, without exaggeration, shot myself in the face with my ejaculation after all of this.