It is normal for the first time to be short and the second time to be long. The first time may be the sensitivity of the glans increased, easy to lead to ejaculation too quickly, while the second penis sensitivity and central nervous system excitement decreased, the phenomenon of prolonged coitus time. In addition, the first time the coitus time is short, may also be mental tension, anxiety, sexual experience is not enough, the central excitability is too high and so on caused by the appearance of short time. If you experience the first orgasmic ejaculation, it will be easy to make the sexual excitement and ejaculation threshold increase, causing the phenomenon of prolonged sexual friction time. In the first sexual life, you need to relax, do not be overly nervous, etc., but also pay attention to sexual hygiene, do not be too rough, so as not to cause damage to the vagina. If you suspect that you have some kind of physical disease, you should go to the hospital in time to get the doctor’s advice.