No - it is not dangerous and you will not cause permanent harm IF - and I do mean IF - you go slow and use excessive amounts of lube. Make sure your nails are trimmed, no cuts in your hands, wear gloves if you can/will, be patient. When you hit the limits of him being comfortable pause there and just hold the pressure for 20-30 seconds then slowly withdraw your hand. You do this repeatedly and over time you will slip inside him - and from personal experience you will both be amazed at the pleasure it will provide.
It is and can be safe.... use plenty of lube, go slowly and wear latex gloves. As a gay man, many men who practice this have no problems
It also tears the tissues inside the victim to the point if done to the anal opening enough the victim will end up wearing diapers because they can no longer hold their poo in. Stretching a vagina out unnaturally is also tearing the tissues inside and could cause blood clots which can work their way to the brain or heart and if you are a man and the vagina is all stretched out you will find there is no longer any pleasure or sensation left with that person and you will either throw her away or have an affair with someone else who has a tight vagina. So isn't this fun what we can do to a woman, use her getting our rocks off and when we are done we throw her away and find another and that victim is ruined for life but who cares there are so many new women and young men coming into BDSM there is a never ending supply and as us, the Master we just have our fun at the victim's expense. This Master will never do that to his sub/slaves ever and will not allow it to be done to them by anyone else I will protect my property.
Just go slow, use lots of lube, wear a glove, and always have a safe word. If you do that then things will be just fine!
maybe try something else freaky and equally exciting but i'd stay away from this kinda thing for a while just not a good idea with all kind of diseases floatin around not worth it if u ask me plenty of other ways to experience sexual pleasure its just to risky oh and if u are going to do it anyway cause when i was ur age i never took good advice or what i now consider to have been good advice just make sure u research the crap out of it dont have cuts on your hands wash hands very good before and after heck use gloves and discard immideatly afterwords i dont know its just not a good idea to risky in my opinion but you are ur own person so you have evryright just don screw up ur whole life because of some sexual act. and make sure you really know the persons health history and just if this person is really someone you want to share this with and if you really trust the person not to hurt you idk seems to complicated to me but goodluck in w/e u choose
There are 4 types of prostate massage. One of them is Anal peripheral prostate massage. This massage can be done on male and female. This would be safer and beneficial than random fingering and fisting.. Google prostate massage for details.
Not from personal experience, but I recommend using just a single finger. That's enough for the feeling. More isn't better in this case, and one would want to avoid any future problems.