Whew boy, this was so long ago that I almost didn't realise I was the one who posted it. Might as well update on recent progress.
So, it's been a while since I took a break from the fetish stuff, but recently I've come back to it and had a much better time overall.
First, poop: This is still an annoyance for me. It's probably because of my shitty diet, but no matter what I do, even with pre-play enemas, I find I have to be a bit careful and eventually stop to poop at some point during play. Having a towel or something under me just in case helps me relax and worry less about getting shit everywhere, too.
This is important because I also realised that the "urge to poop" sensation is actually the thing you want. It happens even if you really don't need to go and after a while you can learn to enjoy it without freaking out. The other thing is that contracting your pelvic floor muscles (like when you're TRYING to poop) is a massive part of building that orgasm, and you need to be able to enjoy and go with that. In some ways, pleasurable anal play is like pushing out a never ending dump as it stimulates your prostate, though that imagery isn't exactly erotic (unless you're into that I suppose).
Anyway, as you can see, if you're having trouble and worries about keeping the pipes clean, anal play becomes quite a bit more challenging, especially if an "accident" puts you off trying for a while. But, I can say that personally, I think it's still worth it. The sensations and contractions involved are so much more intense than anything from a penis.
I'm still exploring further right now. I'm not sure if I've really experienced a proper orgasm yet. What usually happens is that the pleasure will build and build and build until my body is too tired to continue and I have to back off again. I've never reached what feels like a point of no-return like with penile stimulation, and perhaps that simply isn't a thing or I'm not there yet, I don't know. With a combination of both pelvic floor contraction (pushing) and simultaneous anal contraction (like closing your hole - it takes a bit of practice but you can do both contractions at once) with continued prostate stimulation I DID end up squirting a boatload of... something out of my penis, but it wasn't at all like cumming (the fluid was clear with the consistency of pee, but it didn't smell like pee).
So yeah. I'll try to remember to update again if I get anywhere else with it. The main positive at the moment is that I can satisfy myself with anal only. The last few sessions I've had I didn't feel the need to finish off with a traditional ejaculation (I don't want to allow myself anyway to see if it changes things, but I also really just didn't feel like it). And that's good because it makes the prospect of chastity a lot more exciting.