The risk of this technique is developing a vericocele (I'm not sure of the spelling), and this is a pain usually in the left testicle. It is not very pleasant. This is why I don't do the technique very often. I've found though that when the pain does develop, it takes a series of normal orgasms to clear the plumbing so to speak. I have no idea if it can create long-term damage or not.
to Wiff. I am devasted by retrograde ejaculation(RE). Mine is the result of a prostate reduction operation called TURP. I would rather have the messy semen come out of my phallus(penis)again. After 5 months not only are my orgasm's dry(R.E.)they give me no sexual tension release. In fact I become more tense and depressed. Urologists minimize this permanent "side effect"(i.e. main effect- I have to self catheter again so my dubious super enlarged prostate according to a urologist out to make money so logical conclusion: enlarged prostate was not the cause of my urinary retention.) Before turp I could not pee very well and had to self catheter so urine would not build up to infect kidneys and so on. But I could still have satisfying orgasm whether via masturbation or with a female partner. To me being inflicted with iatrogenic(caused by the "treatment", surgery, doctor, etc)permanent dry orgasm(RE) is no longer being a human being. If there is anything at the core of the human race is reproduction and sexuality. Quite frankly, to me, I am afflicted with a condition worse than death.
I have the same problem and I cant believe that the medical profession can think that retrograde ejaculation should feel the same as normal ejaculation. I hate it and there is just no explosion. I wonder how they did research if any about the quality and satisfaction of a climax after the TURP operation. I think that they should do research with men under the age of 60 and not above 60 and then see if the men still think that sex feel the same after the operation than before.