I just read a technique by GAZ where he just 'thinks' himself to orgasm. He is absolutely correct. I have been doing this for almost 20 years now.
You have to have a lot of time and be able to concentrate on your feelings and not sexual situations. I sit in a recliner chair and stare at and concentrate on the head of my cock and my balls and concentrate on what it feels like when I'm nearing an orgasm. Within 15 to 20 minutes I will start to get hard and the feelings will start to become intense. I can keep this up for an hour or more.
The longer I do it, the better it feels. After about an hour I will start to precum and my cock will be harder than a rock and twitching. I just keep concentrating on my cock and balls and the pleasurable feelings I am having. Then it will start to happen! I can feel the cum rising inside my cock and the pleasure is so intense it's almost unbearable. I will cum and cum until I am exhausted.
It helps if you haven't had an ejaculation for several days and you probably won't be able to achieve the results you want the first few times you try it, but if you keep it up, it will happen. It is the most erotic thing on earth.
I've often wondered what it would be like to find another guy who can do this and put two recliners facing each other and stare and concentrate on each other's cocks just to see if we could have mutual orgasms without touching ourselves or each other.