Prostate orgasm definetly achieved. Any advices?

Hi everybody, I would like to share this experience with you and ask some advices:
After 3 months of trials, me and my gf finally succeded in having me cum while caged just from prostate massage. She's became a pro at It. She made me shot like half of a tea-cup of cum without feeling nothing more than the sensation you feel while pissing.. I've been hard in my cage for another 15 minutes right after we were done. And I sadly discovered that I can't do It myself, I just can't achieve It. She said that she would be happy to make me cum only in this way from now on, we decided to give it a go.
Now I was wondering:
- Could it be in anyway unhealthy?
- Could It prejudice my erections?
- Would It be better using this method just for a fixed period of time?
- Have you ever achieved something like that? Thanks mansion