slowfast

Hi guys,

I'm a 25 year-old male and here is my scenario.
I have no problem with erection during the first intercourse. When i am about to orgasm, i stop and i withdraw, and i continue again after the urge to orgasm has subsided. I keep repeating this process 4 to 5 times because i want a longer lasting sex.
However, during the 6th time, I have problem getting an erection. I do not know why? Am i the only one having this problem? Anyone out there has any idea on how to solve this?
Any help would be great.
Thank you.