Dildo and thrust
A very different way to stimulate the prostate than the other techniques discussed is basically to fuck yourself. Reaching a prostate orgasm this way is something you learn to do long after learning to do it the other way, although your mileage, as always, may vary. But glad to have learned to do so. This is a particularly interesting orgasm because penetration and penetration evokes many other sensations at the same time.
The difference between this method and using a probe is that there is not much thrust with the probe. Most of the time, it's rocked back and forth, not in and out, so there's not much stimulation to the sensitive tissue around the anus, just the prostate. On the other hand, what I'm thinking of here is a form of play that's more focused on getting in and out of anal ring with a lot of stimulation.
What size a person wants is largely a personal decision. But here, it's important to be able to get in and out of the dildo in a regular, rhythmic fashion, so you want something reasonably comfortable. You need a lot of lube.
Simply inserting a dildo and moving it in and out will not provide much stimulation to the prostate. The prostate is located in the front wall of the rectum, so dildos that point directly at the rectum will mostly miss it. To stimulate the prostate in this way, you have to rub the dildo over the prostate or back and forth. To do this, you must tilt the outer end of the dildo away from the front of your body so that the part of the dildo inside you is pointing towards the prostate.
This angle can be difficult to get right. If it is too steep, the front end of the dildo will hit the prostate too directly, which is uncomfortable at best and painful at worst. If it's too shallow, then you won't be able to put enough pressure on the prostate. More than any other technique, you have to experiment almost every time until you find the right angle, which may not always be the same. What works best for me is when I can find an angle where the dildo bounces off the prostate every time it is inserted into me, the tip hits the prostate and the body slides along it, then reverses the process as the dildo pops out of me body removed.
The right dildo will come into play here. The advantage of glass and metal dildos is that they are very slippery, and very slippery with just about any decent lube. However, I found that really hard dildos often seemed to hit the prostate too hard. On the other hand, if the dildo is too flexible, then it will be pushed away from the prostate without providing much stimulation. So you want something in between, something that will hit the prostate with some force, but bend just enough to move along the prostate as the dildo goes on, rather than keep pushing into it.
I've found that silicone dildos are generally suitable for this use. On the other hand, I found that they didn't get very slippery even with a good lube. The most slippery lube is a silicone based lube, but of course you can't use a silicone based lube with a silicone dildo (unless you want to melt it down). Using a condom on a dildo helps a lot in my experience, and of course it's easier to clean up too.
Dildos don't specifically need to bend, a dramatic curve that interferes with the in and out movement you're trying to achieve. Gentle curves can be useful, though, as can a larger-sized handle. Also keep in mind that any device used for anal penetration should have some sort of "flange" so it doesn't get lost in your body.
Doing this solo, I found it difficult to find a comfortable position that would allow me to both achieve the correct angle of penetration and get enough power after the thrust for a truly satisfying experience. Lying on my back, it was nearly impossible to reach far enough to tilt the dildo the right way, even though I used the pillow to tilt my hips up. The style works a little better because when I grab the dildo with my arms behind me it naturally pulls it towards my back so it helps to get the right angle. But with one hand on the dildo, I only have one arm to support myself, which can get tiring quickly. Usually what works best is if I lie on my side and put my hands behind me. This is an easy-to-maintain location. Lying on my stomach (ie simply lying on my stomach) also works fine.
It's a great way to play when I'm in the right rhythm. I can use shallow angles for a while and just screw myself without worrying about my prostate. That in itself feels great. As I mentioned before, the tissue around the anus is very sensitive and it increases my arousal until I'm ready to orgasm. At that point, I can change the angle to stimulate my prostate, have an orgasm, go back to having sex on my own until I'm ready to orgasm again, etc.
Hands-free
If you had a partner who could manipulate a dildo for you, I doubt the game would be easier, although I admit I've never had that kind of fun. And, obviously, if you have a partner who's ready to wear a dildo, or a partner who has a fleshy dick of his own, there are all sorts of other possibilities for you to explore. But I haven't had the fun either, so I won't comment on them.
However, there are other ways to "free your hands". I had some luck installing dildos. For example, a few years ago I had a vibrating dildo that died. So I take the vibrator off the base and fit what's left on the end of the broom handle, or something like that, and then I can wedge it firmly under my mattress so that when I do it it will not move. Then I could get on my hands and knees, insert the dildo, and rock myself back and forth so the dildo would go in and out of me. This is good for simulated intercourse, but it is difficult to get a good angle to stimulate the prostate. Likewise, many seat belts, especially thigh leather
Items like seat belts, which can be attached to pillows, or wrapped around sofa cushions, or what have you, and then you can attach dildos to them. There are also various types of sex furniture that can accept dildos, and these can also be used. However, this doesn't work well for serious thrust, as there tends to be too much "game" in this setup. That is, when I do, they move too much.
But there is a different technique that sometimes works well for me, which is sticking the dildo all the way in and rocking my hips back and forth on it. This results in some slight in and out movement, but is mostly a prostate massage that pushes the body of the dildo towards the prostate as my hips swing back, then releases the pressure as my hips swing forward, and so on, ending and end. It's a great "active" way to play, and it gives your glutes a nice workout.
I recommend experimenting with your "resting" position. If you move your entire body forward a little so that the bottom of the dildo moves back, the part inside you will move towards the front of your body, towards your prostate. If you move your body backwards, the dildo will move away from your prostate. This allows another level of control over the amount of pressure applied when rocking the hips.
In conclusion
Well, we've seen that there are several different ways to stimulate the prostate, which can lead to a prostate orgasm. Not all of these methods will work for everyone, but they have all worked for me, at least at some point or another, even though some of them are more reliable than others now. No one knows what will work for you, and as I said, learning how to orgasm in a new way takes time. Only through practice and experimentation can you discover what works for you and what doesn't.
But if you're wondering whether to start trying, let me put it this way: you don't know what you're missing. If you do, you don't doubt; you start now. As far as I know, prostate stimulation provides a depth and variety of sexual pleasure that a prostate patient cannot obtain in any other way.