If you want to enjoy anal sex, you have to prepare your body. A short time prior to anal sex, some people include cleansing as part of this preparation. Immediately prior to anal sex, without fail, some manual anal play is a very important preparatory step. But we'll discuss these two things a little further on.
Before all that, there is solo, self-preparation. I don't think any sex expert, or even any amateur sex advice would recommend having sex with someone without first learning about your own sexual responses first. In other words, learning to masturbate before sex will give you a better first sex experience. This basic piece of logic seems to be forgotten whenever talk turns to anal sex advice. But the truth is that people who already know about their own ass, know what feels good and what doesn't are the ones who enjoy anal.
Learning About Yourself
It's all about experiencing the touching and penetration you might when you play with your partner. But you need to start slow and by solo.
The first reason to start slowly and by yourself is, just like with "normal" masturbation, you need to learn about yourself. Find out what you like. Learn what makes you feel good and very importantly, what might hurt you.
Learn how long it takes to get a finger in, what angle works, how aroused you need to be before you even want anal stimulation. For some, anal play is something we desire right from the start, for others, it's something that only gets the green light after our first, second, third orgasm. Everyone is different and you should know your personal preferences.
Once you know how your body reacts to different types of anal stimulation, this will enable you to communicate properly with your partner. When in the receiving role in anal sex, you are the co-pilot. You're sitting in the passenger seat with the map. If you've studied the map and driven the route a couple of times yourself, you'll be able to give directions better.
"Ok, slow down... No, much slower. Yes, that's good. Right turn up ahead.."
If you don't know what is going to feel good and what will feel bad, you have to wait for something to happen before you can give advice. More like "Ouch, no, don't do that. Ah! No, that doesn't feel good either...."
If you know what will feel good, you can guide the driver there.
Long Term Preparation
Do not dismiss this form of preparation. This is the main reason people don't enjoy anal sex their first time.
Anal sex is like running a marathon. If you aren't a runner and you decide you are going to do a marathon, sign up just before the date of the event, then run, you are going to have terrible experience. You probably won't finish. You will be in pain. You may injure yourself seriously. You will reconsider ever signing up again.
To succeed, you need months of training. The secret to success is slow and steady. Gradually increase your training until the event.
My opinion is that you shouldn't try anal sex unless you have already had something penis sized up your butt. You need to train.
Training for Anal
The following advice is meant for you to do alone but it can also be done with a partner. If you've never touched, fingered or put something up your asshole by yourself and your partner says "Hey, let's try anal sex!", your immediate response should be "Let's work up to it." Follow this long term roadmap to successful anal sex.
Tell him you are willing to try but you've never even touched yourself so the only thing you want to try tonight is touching your asshole. No penetration. If he's willing to go slow and gradually introduce anal play into your play time, then you might eventually try getting his cock up there. But you want to go slow.
And slow means slow.
Initially, all you want to do is touch or gently rub your asshole while you enjoy some vaginal stimulation. Or if you are with your partner he or you can do this during PV sex. Or while he is going down on you. Whichever scenario, keep that ass finger away from your faces, vagina, penis and sex toys until you can wash it. Cleanliness is important!
Once you are comfortable with touching the outside of your asshole, it's time for just the tip. Just the tip. Of your finger. And not even that much. And it's going to go better if you do it yourself. Any guy who wants to put their finger up a girls ass (which is a requirement if you want to fuck it) should have done this to themselves so they know exactly how to push their finger into your asshole.
It's not simply a matter of pointing your finger and pushing it in. It's more like massaging your finger through the sphincter muscle. Stroke your finger over the center of your asshole. Then add a little pressure. Continue to add pressure while relaxing and your finger will push through. Don't try to keep pushing it in, rather stroke through and let your finger slide out. So really you're just penetrating the outer part of the sphincter.
Doing this should relax the inner sphincter that you have no conscious control over.
Once you are comfortable with this, slide your finger in deeper. Slowly. Take your time to notice how it feels. Don't try finger fucking your asshole. It's much too delicate for that. Just enjoy slowly pushing your finger in and taking it out.
The next step is trying something a little bigger. Longer or thicker, the size is up to you. You may be tempted to use things from around your house. My younger self certainly did on my own journey of anal sexual self-discovery but if you do, be safe and clean by covering things with a condom. The best thing is to buy some sex toys.
Sex Toys for Anal Beginners
If you are an anal beginner, the goal is to try things that are enjoyable. What you won't enjoy is something too big. Too big means pain. Or more likely, an unused toy and a negative perception of sex toys and anal sex which means you have just written off tons of potential sexual fun and pleasure.
So start small.
Two sex toy varieties I enjoy and recommend are anal beads and butt-plugs.
Within the anal beads category, you might see the bumpy dildo type and the balls on a string type. Do not try the balls on the string type.
The father of a childhood friend was an emergency room doctor. One night I was sleeping over at her house. Her older brother had friends over too. Her father was relating to these boys the story of a man who came into his emergency room with ben-wa balls stuck up his ass. The string had tangled and with the balls clumped together, he couldn't remove them. Fun going in. Expensive and embarrassing coming out.
So yeah, go with the anal beads that are a single, solid piece of plastic. (Preferably silicone.) Not only could the stringy ones get tangled up inside your ass, but the string is likely to absorb any juiciness it finds up your ass, and the holes in the balls the string needs to go through would be impossible to clean.
Start small. You can easily find beginner sized plugs. You can even find beginner sets, with three or so plugs, each a step bigger. These are great for experimenting by yourself but also work really well, once you're ready, for playing with your partner.
You might find it easy to take a 1 inch diameter plug by yourself but with a partner, pressure and nervousness can make previous accomplishments feel a bit too tight. Having the smaller ones on hand helps a lot when warming up for the real event. It also helps remind you both (mostly him) that warm up need to go slowly, step by step.