I used to work in a porno shop years ago and this lady I worked with was an older lady, and her husband had ed and the doctor gave him some kind of steroid shot in the muscle right at the base of the penis and somehow it gives you wood. She told me she would administer the shot and had to be really careful. I had also heard of some of the pornstars that would do that for long lasting wood.
I dont think I would want to try it though....