Brachioproctic eroticism is the technical term for the slow, gradual insertion of a body part into the rectum for sexual pleasure. Usually brachioproctic eroticism refers to the insertion of a hand, fist, or arm into the rectal cavity. However, this term can also refer to the similar insertion of a foot.
Brachioproctic eroticism is also called brachioproctism. When the body part inserted into the rectum is a hand or fist, the slang terms fist fucking, fisting, or hand balling may be used. However, these terms can also be used when these body parts are inserted into the vagina. The term for this practice is brachiovaginal eroticism.