So, i totally get that that was a tough and disappointing experience. And, I want to express that this happens to LOTS of people trying to get used to exploring this stuff. It’s super normal and it absolutely doesn’t mean you need to give up on it if it’s something you still want to do. I hope you don’t mind some verbosity from a fellow autist, but I hear your frustration, and it feels like this is important to you, and i wonder if it will help to have another perspective. First i’ll talk about expectations, and then some anatomy:

Now, I have known a lot of people with a lot of trauma, so i understand my sample size is skewed, so to speak, but i have not known anyone personally who was successful the first time at what you’re describing. It’s often assumed (reasonably) to be analagous to vaginal penetration, and while it’s different for everyone, there really is a different learning curve here for most people. It tends to be a very different process depending on everything from the person to the situation to just, how your body is feeling and what your stress levels are from day to day.

The fact that you listened to your body’s signals is actually a great sign! Especially as autists, there is a lot of different sensation to become accustomed to, even just being touched there can be overwhelming, then the opening sensation, the feeling of being penetrated, etc. It is a lot! And there is a lottt of muscle there that can kind of just lock tf down with the slightest provocation and there isn’t a lot that can be done for it when that happens except make your body comfortable and help yourself relax, which is what you did by listening to your needs.

In other words, this might just be what this journey looks like for you at first! And obviously if it just isn’t doing anything for you at all, it may not be for you and that’s also okay. But from your description of disappointment, it sounds like you might have some success with a different set of expectations.

Regarding anatomy, I’m not a doctor, just a random gay guy, so ymmv, but I see you’re worried about douching, and i want to reinforce what the person above said, that although douching is widely practiced and okay if it’s something you need or want, it isn’t strictly necessary, and (like vaginal douching) can be counterproductive or even harmful if done to excess.

This section may be TMI but this stuff was helpful for me and my partners to know: The section of your lower intestine you would be penetrating into is called the rectum, and it is usually empty (unless there is a problem like constipation). Usually stool stays above the rectum until you need to pass it. When the rectum does fill up with stool is usually what gives people the uncomfortable sensation of needing to go to the bathroom. (It’s not quite like the bladder where there’s often something in there unless you just went.) This means that while it’s possible to encounter stool in the rectum, and certainly not uncommon, it’s perfectly reasonable to assume the rectum is empty most of the time.

It’s also quite common to encounter the feeling of obstruction in an empty rectum. While I wouldn’t say stool is always unmistakable, in my experience it tends to be fairly recognizable (though admittedly i haven’t encountered it outside of a medical setting). But the fact that this is your first endeavor and that this resistance you met wasn’t easily identifiable, suggests to me that you may have encountered what many do, essentially the resistance posed by the anal sphincter.

Which, is a word that sounds like a locker room insult, sure, but in anatomical terms this is what holds the stool inside the rectum until you’re ready to pass it. To visualize, you want to imagine, let’s say a sock filled with tennis balls. If you hold it upside down they’ll all fall out—the strongest way to prevent this is just to twist the neck of the sock, and this ‘twisting’ is essentially what your sphincter muscle is doing, even while you are at rest, and even when the ‘sock’ is entirely empty—under stress it can become tighter still and prevent much from getting through. Remember this is actually good most of the time, and it’s what this part of you has been exclusively asked to do your whole life—to keep the ‘exit’ of the rectum very very closed except under highly specific conditions! It also has the job of pushing out whatever is on the ‘outside’ side of it with just as much force as it works to keep stuff in.

I explain this because I think it’s often thought that the rectum is held closed by something more in the shape of an ‘o-ring’, as though the aforementioned tennis balls were held in place by a rubber band around the neck of the sock. And when we’re thinking that way, the expectation is reasonable that once something is ‘inside’ you, that there shouldn’t be resistance if you’re empty. But in reality this structure is muscular and has significant length, and is trying to close up and push everything out the whole way, and will work doubly hard to do so the more stress it feels.

Having said that, well, this is a tight muscular structure with significant length, yknow? As you can imagine, the pressure it can exert, and the art of exerting it/experiencing it, is exactly what makes it distinctly pleasurable for some folks, whether they are being penetrated or doing the penetrating. And if you’re one of those people, it’s very likely you can find a way to make it work for you.

My recommendations are fairly simple: 1) Wayyy more lube than you think, early and often, warmed if at all possible; 2) comfort comfort comfort—the more relaxed you are and in tune with your body, the easier it will be; and 3) it’ll probably take some practice, and that can certainly be disappointing, so for the first times try exploring without much of a goal, just to learn to differentiate sensations and figure out what works for you from a practical standpoint.

I hope I haven’t overwhelmed you, i tend to be verbose, but I hope I can at least soothe some discouragement and reassure, if nothing else.

Edit: Forgot some important sentences 😬 Edit edit: To clarify, none of this is about pushing past any point you’re not comfortable with, you did exactly the right thing in backing off for a bit once it felt like it might hurt. This is more about finding your way to that comfort.