I have had this happen my whole life. It is not something I would consider lucky. I will spend 3 and a half to four hours mastubating get tired and never cum. The next day maybe just 2 and half hours and give up, the next day or two I find I'm so wound up that I can cum quickly about an hour and a half, on average it takes about 8 hours that is knowing exact pressure speed, with a partner about 14 hours if at all. Never once vaginally. The thought of 5 minutes is unconcievable.
You have to rub your Clint Vagina, anal can take way to long. How old are you?