Very dangerous! Do not ever wear a cock ring for more than 30 minutes without taking it off for a break or you risk losing your penis and/or a long stay in hospital with blood poisoning. Or of course death.
As others have said, there is no way to make your penis bigger permantly and no reason to do so.
Just like the avengers arent real, porn isnt real either, most men are the same size as you or smaller.