How come I'm barely 14 and getting an erection takes 25-40 seconds but it doesn't usaully stay erect?
The male body isn't designed to hold erections for more than 30 minutes. This is because a erection is caused by blood flowing into the penis and not flowing out, making the penis inflate. But since the blood is barely flowing, the oxygen in the blood eventually gets used up. Without oxygen, the cells in your penis start to have trouble and you end up in pain. Therefore, your body inflates your penis, but if a need for an erect penis is not there, it lets the erection go so blood can flow again through your penis.