There is no specific limit to how many days after circumcision you can have an erection. It is possible for teenagers to have an unconscious erection of the penis. After circumcision should pay attention to rest, keep the skin clean and hygienic, change the medicine on time, prevent wound infection, at the same time underwear choose loose and comfortable clothes, avoid contact with unfavorable sexual stimulation, reduce penile erection, if frequent erection may cause local edema, incision crack, etc., which affects the recovery of function. About a week after circumcision, the wound is basically recovered, you can remove the sutures, postoperative sex is recommended to wait a month before sex, avoid premature sex, so as not to aggravate the edema reaction, affecting the recovery of function. After circumcision, if there are uncomfortable symptoms, you should promptly seek medical attention.