It is a normal phenomenon for boys to easily get up in response to the natural reaction of sexual physiology, especially in front of their beloved and heartwarming girls or in the morning when the penis is more likely to get erect. This is also a manifestation of normal, healthy and mature male sexual function. In addition, if a guy wears tight underwear or unintentionally rubs his penis, it can also lead to an easy erection and response. In this case, the boy should consider changing himself to a loose underwear. Of course, if a man has an abnormal erection, it may also lead to a guy being prone to react. If the ding is persistently painful and erect for more than 3 hours without the sexual urge, or if the ding remains long and erect after fapping, you should consider abnormal erection or non-ejaculation, and you need to seek medical attention at this time.