Feeling something moving in the anus is called a foreign body sensation in the anus. The more common factors for this condition are hemorrhoids, inflammation of the anal sinus, inflammation of the rectum and other common diseases of the anus, and it is necessary to exclude the presence of parasites. If you wear tight underwear or have poor anal hygiene, you may feel a foreign body in your anus and feel that something is moving. If you’re looking for a good diagnosis, you’ll need to get the right treatment. The common diseases at the anus, such as hemorrhoids, sinusitis and rectal inflammation, are mainly treated conservatively with medication, and if there are parasites in the intestines, you can take oral worm-killing medication.