Anal fisting is a sexual practice in which one partner inserts a hand into the other's rectum through the anus. The practice is similar to vaginal fisting. The person who is inserting their hand is called the Fister and the person receiving is called the Fistee. The hand is not actually in a fist position during insertion. To slide the hand inside the anal cavity past the anus, the fingers must be extended and overlapping in a cone shape, sometimes referred to as duck-billing or the "silent duck." The most successful positions to achieve full-hand insertion are with the person lying on their back, in the doggy position, or in a sex swing. Gradual insertion stretches the anus to accommodate the fingers, knuckles, hand, and thumb until eventually retracting again around the wrist. Once the hand has fully entered the rectum, the fingers can be clenched into a fist. Anal fisting is mainly a partnered activity, though some people can achieve the act during masturbation. More extreme variations include double-fisting, punch-fisting, and moving the fist in and out of the anus. Anal fisting is sometimes referred to as handballing or fist fucking.
The anus is a muscle and like all muscles should gradually be stretched and trained to accommodate this kind of play. It is not recommended for newcomers or anyone who has never practiced anal play or fisting before. With all BDSM activities, responsible play is key to achieving maximum pleasure and enjoyment for all parties concerned.