There are two main reasons for the feeling of anal swelling during coitus. First, physiological reasons, mainly due to the more intense movements during intercourse, the vaginal stimulation is relatively large, which leads to the anal area is also more obvious muscle spasms, triggered by the feeling of anal swelling. In this case, generally after intercourse will soon be relieved, do not need special attention and treatment. Second, pathological factors, common hemorrhoids, rectal polyps, cervicitis, pelvic inflammatory disease, etc., is due to coitus squeeze hemorrhoids, polyps, or stimulate the inflammatory parts, will cause anal swelling. General hemorrhoids, rectal polyps patients will often be accompanied by blood in the stool symptoms, gynecological inflammation patients will most likely have increased vaginal discharge, chills, high fever and other symptoms, and most of them are persistent episodes, there is no obvious time interval. In this case, it is recommended to go to the hospital in time to determine the condition, and early treatment.