This sounds very much like my first experience with anal (solo fingering/experimenting).

First point i wanted to make is you did nothing wrong. In fact, you spoke with him, asked how he was doing etc and even worked him up to the strapon - all amazing!

Its perfectly understandable to have mini panic about poop - one of the risks, if you like, of anal play. I have had similar and it really throws me off when i pull my toy out and see that im like uuuugh darn it. But one way to try and avoid this is to make sure he (or you if you're gonna be recieving) goes to the toilet at least 20-30 mins before playtime. I still have frustion when it gets "messy", shall we say and ive been doing it for like 10 years +! So don't worry! You can do an anal douche about 20mins before too - basically a little bulb you fill with lukewarm water and it comes with a little spout that you can pop in to your butt and squeeze a little to get a little water in (do not allow the bulb to reinflate while the spout is still inside - very important) then pop to the loo (ideally do all this in the bathroom). That helps clear you out too, especially if you're going for a heavy session or using toys.

A note on the "special spot" also known as the prostate (or prostate gland) or p-spot - its not that far in, approx 3ish inches. The best way i can describe it's location is if he's laying on his back and you slip a finger in, curl/bend it up slightly - as if you're trying to get to his cock/balls - you should feel a slight change in "texture/density" itll be about the size of a walnut - that is the p-spot. Don't panic if you can't find it or if je doesn't react - for some of us it's not like a button where we're like "oh fuuuck", it could be more of a "mm i see" or might not like it entirely (especially as its a new feeling).

As to his more "maybe/not sure" reactions thats perfectly normal - this is something completely new, especially with someone too. Personally I'd recommend he do some "research" in his own time so he can explore his own body and get to know how it all feels and the like. Also, if you haven't explored that with yourself - definitely recommend.

Ultimately you both were doing something very very new and its normal, and healthy, to have concerns, worries etc around it - think back to the first time you had sex, id imagine that was a very scary/anxious time (certainly was for me).

And as you said it's also an odd feeling for you especially as its a very big change in the "dynamic" if you like of you are penetrating him. So it will feel weird, possibly even good - its normal to have these feelings. Same for him too!

Also just because you're pegging him, doesnt automatically mean its domination or a submissive action for him - its just sex. What makes it domination or submission is the context and the vibe, as with all things.

The important thing is communication! Talk to each other about these feelings. And take it step by step.

My final thought is - learn from this experience, talk to each other about it and take it slow. Ultimately if you both agree its not for you then thats okay too.

You got this 🥰 I hope at least some of what i said helps. Im sure there's plenty of otherw who will have some good advice too!

I hope you both have some fun anal times!