Exactly what causes haemorrhoids is still somewhat unknown, but we do know that they are caused by increased pressure in the anus. The upright posture of humans alone forces a great deal of pressure on the anus, causing venous walls to engorge with blood and swell.
Common Causes of Haemorrhoids
Anal infection
Constipation or hard stools. (most common cause)
Lifting heavy objects (repeatedly)
Low-fiber diet
Pregnancy and childbirth
Severe coughing
Sitting in one place to long
Straining while moving bowels
Other Haemorrhoids Causes:
Aging
Anal sex or infiltration
Chronic diarrhea or constipation
Excessive rubbing or cleaning
Frequent use of laxatives or enemas resulting in faulty bowel function
Heredity
Too much time on the toilet
The bottom line is roids may be caused by stretching rectal tissues too much and too often. As a result rectal veins dilate and the venous walls become thin and bleed. If stretching continues, tissue becomes weakened and protrudes out of the anus.
Haemorrhoids cause itching and irritation by protruding from the anus. It's important to keep the rectum clean and dry. If symptoms persist, apply an anti-itch cream like Hydrocortisone (1%).
Can or Does Anal Sex Cause Haemorrhoids?
Anal sex would have to fall into the 'excessive rubbing' category. It stands to reason that if forcing objects into a part of the body that is intended to force things out, the misdirection will result in the increased aggitation that causes haemorrhoids so whenever possible, anal invasion should be reserved for the prostrate exam only.
Stress on the other hand is not a likely haemorrhoid cause in and of itself. 'Pressure' is stress in a sense on the rectum which does lead to haemmoroids but 'emotional stress' doesn't result in this condition.