do you have any advice for an autistic adult who hasn't yet lost their virginity due to the social aspect? I'm terrified not of the act itself, that's fine, I get myself off just fine all the time, but that I won't act the right way, that I'll try too hard to be sexy and it'll be cringy or not try hard enough and be off-putting
Oh, honestly, I think a lot of people worry about that a lot of the time they have sex, whether it's for the first time, or the first time they're just trying a new act, or just when it's somebody new or somebody they've not seen in a while.
Sex is ultimately something extremely vulnerable - you're literally dressed down, you're generally in private together, the other person is very concentrated on you and you very concentrated on them - so there can be a lot of concern about how you're going to perform, how you're going to look, if you're going to be sexy or embarrassing, or whatever else.
When I first had sex after like eight or ten years of celibacy after my more active (and abused) life in my teens, it did feel a lot like a sort of virginity, and I basically just had a decently anonymous hook-up with a nice fella on Grindr. He was on the shy side and had some insecurities himself, but for me, the fact that it was so anonymous and low-stakes eased the way for me - you might find that, or you might find that on the other side, someone you already know very well and trust quite intimately will be more comfortable and be more of a balm for your anxiety.
People make a big thing about sex and its social or intimate or romantic implications, but it's ultimately just another slightly silly thing that people do together. It's inherently undignified and a bit absurd, no matter how well a sex scene is edited in a film, and with how great a sound track.
I don't say this to say sex can't be important, or that it can't feel really great or even really emotionally important, because it absolutely can be.
It's just the truth that you and another person or people are also going to be wrestling and wobbling about together, with at least some of your clothes off. You're going to be smelling each other. You're going to be up close, very upclose, with each other's genitals and arses and chests, and armpits and ears and ankles. Now and then, one of you is going to fall over, or accidentally hit the other one in the nose, or put your elbow on the wrong bit of them and make them go "ow!" and you'll lurch back and go, "fuck, sorry!", and sometimes you'll lurch back too far and fall off the bed.
Sometimes, the bed - or wherever else you're getting up to this - will break. Sometimes, the dog will manage to open the bedroom door and leap onto the bed, midway through the act, and excitedly introduce a sodden, mostly-chewed rawhide into the activity. Sometimes one of you will release the most incredibly musical fart in the world, at the worst possible time.
Sometimes, the sex will just straight up be bad. The time won't be right, or you'll have a slight cold and you'll keep wanting to blow it or swallow phleghm and it'll be gross but you'll also genuinely be quite horny, or you and your partner will be slightly mismatched in rhythm and size and keep giving each other unlikely bruises.
Sometimes, you will be utterly nude, you'll be gazing deeply into one another's eyes, your body will feel tense and aching a bit but at the same time, perfect. There'll be sweat sheening on both of you, you'll both be breathing hard and sharing the same breath, you'll have managed a sublime rhythm that seems to be seeping into the very core of you, your orgasm a more distant concern than making this moment, this perfect moment, last for as long as possible, because it just feels so good, so intimate, so loving, so perfect--
And then the fire alarm will go off.
And it will be the absolute worst thing in the world, but also, you probably will laugh about it - laugh uproariously, at the sheer juxtaposition of it, as you either try to quickly finish or stumble out of bed to put on dressing gowns, and hope none of your neighbours or the fire people look at you in too much detail when you're waiting downstairs.
Your concerns about seeming like you're trying too hard, trying too hard to be sexy, ending up a bit cringe, not trying hard enough and ending up flat - you might have these same anxieties going out for coffee with someone, or playing Dungeons and Dragons or improv-ing with someone, or doing karaoke.
You and your partner(s) will be in the same boat of vulnerability when you have sex - they might have the same or similar anxieties to the ones you do. Part of the reason that sex is generally best with someone you trust is because that vulnerability is part of it.
You're trusting the other person with your naked body and how it looks and feels and smells; you're trusting the other person to touch you the right way, use the right lube and prophylactics; you're trusting the other person to basically do rhythmic exercise with you, and that includes all the sweat and physical exertion that comes with that.
There may well be times you try too hard to be sexy, and your partner says "you can probably tone it back a bit", or even laughs - and there will be time when your partner does the same. Other times, you might well be being "too sexy" - as in, sexier than your partner was prepared for - and they'll be incredibly into it, or jump to match your energy.
Sometimes, the sex will absolutely be cringe, but luckily, that's part of having sex, not to mention life, and sometimes, cringe is delightful.
The first or maybe the second time my partner and I had sex, I couldn't stop infodumping about marine biology and telling him exciting facts (I felt) about different creatures' mating habits, which drove him insane, and not only did he still have sex with me that night, we're going to get married.
I'm not saying "don't worry", because social anxiety doesn't really listen to "don't worry", but part of the reason your anxiety has so much mileage in this internal conversation is because sex in your head might still be there as like, a capital-letter activity that requires infinite decorum and consideration and with so much stuff for you to do wrong, and that bubble will burst a bit when you do start having sex with other people and the mystique goes away, but will always be there a little bit.
The tragic thing about sex is that because it's genuinely just a fun thing people do together, your social anxiety has as much reach there as it does any other activity you might pursue with someone, but the good news is that once you have sex a few times, it will hopefully just be the same level of anxiety you do have with any other activity.
"Virgin" is made out to be this big thing, but people are virgins at new activities every day. Driving a car, going out for dinner in a fancy restaurant, wearing suspenders, going swimming, et cetera. It's really not a bad thing to be, but it's also not necessarily a momentous thing to stop being either. You'll be great!