Can anyone prove that it is safe to sit on the edge of the sofa and ejaculate? I.e. ejaculation won't cause muscle and nerve tearing?

well yes i can prove it as i am 51 and i do it that way all of the time and no qualified doctor will ever back this up with any type of proof

Sure, since this myth keeps getting posted every week for the past year, I have done it myself to see if there is no problem, which I knew there wasn't- no medical reason there would be- and I had no such symptoms as you describe.

Why dies this stupid question keep getting posted??

The proof is that I have done it hundreds of times with no adverse effects. However if you still prefer to sit cross legged on the tatami while you jack off then feel free to do so.