Pain in the penis after oral sex may be caused by epidermal damage to the penis due to overly vigorous movements or teeth cutting into the penis. It can also be caused by inflammation of the urethra and prostate gland due to parasitic flora from the mouth entering the urinary tract. The oral cavity is not a regular part of sexual intercourse, so tooth bruising or excessive friction can lead to penile trauma. The first thing to do is to observe whether the skin of the penis is broken, and then do not have sex or masturbate for a while. If the pain is relieved after a period of rest, then there is no need to worry, fully learn the sexual skills and then have sex to avoid such events again; but if the pain lasts longer, then you need to consider the possibility of inflammation and infection due to unclean sex, it is recommended to go to the regular hospital male or urology department, under the guidance of the doctor treatment and medication.