A very itchy asshole is not necessarily a hemorrhoid, the asshole in this case is talking about the anus. There are particularly many reasons for anal itching, it could be anal fissures, where the stool is relatively dry leading to fissures in the skin of the anal canal, so every time you have a bowel movement, the stool or mucus can stimulate the trauma of the fissures and cause itching, sometimes with pain. Anal itching may be caused by fungal infection of anal eczema, which can form radiating fissures in the skin of the anal canal and often secrete some mucus leading to perianal dampness and itching discomfort. The itchy anus may be caused by itchy stools that are often unformed and then often come out along the anus, and the itchy anus is caused by long-term stimulation of the perianal skin by feces, which is more common in older people with a relaxed anal sphincter.