There are some interesting articles on your web site, but I thought I should what used to be one of my favorite techniques. I don't do this now, simply because I don't get the urge anymore. Perhaps it was a passing phase, but I certainly had some good orgasms from it. Basically, what I used to do was somehow squeeze my nuts pretty hard a few times then masturbate. This soon developed into a technique where I 'crushed' my balls for 5 or 10 minutes then masturbated. Masturbating took away the pain (which was pretty erotic to me anyway) and produced a great orgasm.
Looking back, some of the ways I crushed my nuts seem pretty mad. They included putting them in the hinged part of a door and pulling it shut. I remember one time when I must have pulled it just too far and caught the wrong spot, as all I could do was curl up in agony, although I remember the orgasm after than was especially good. Again, this progressed further into putting my nuts under the toilet seat and pushing down before masturbating. This in itself lead to some stuff that was really scary now I think of it, but was great at the time. Basically, I used to go from just pushing the toilet seat down to putting my full weight on it, and even lifting my legs off the floor! I got to the point where I was orgasming just from crushing my nuts like this. As well as this, I also used a vice to crush my nuts, often to the point where there was so much pressure on them they used to pop out of the jaws against the 'pressure gradient' or whatever the technical term is.
One last incident to mention is the only time I was kicked in the nuts was by my sister. I basically asked her to do it as I wanted to know what it was like. I told her to start gently, but of course she waded in with a nice, solid, crunching kick. Naturally, I curled up in agony but after a few minutes there was nothing I could do but masturbate myself, even though she was sitting on the bed watching TV while I laid on the floor. On reflection, I suppose I'm lucky to still have two working testicles, but it was fun.