Anal masturbation is an autoerotic practice in which a person masturbates by sexually stimulating their own anus and rectum. Common methods of anal masturbation include manual stimulation of the anal opening and the insertion of an object or objects. Items inserted may be sex toys such as anal beads, butt plugs, dildos, vibrators, rectal thermometers or specially designed prostate massagers or enemas.

Pleasure can be derived from anal masturbation due to the nerve endings in the anal and rectal areas.

In men, orgasmic function through genitalia depends in part on the healthy functioning of the smooth muscles surrounding the prostate, and of the pelvic floor muscles. Prostate stimulation can be especially pleasurable because it stimulates sensitive nerve endings. Some men find the quality of their orgasm to be significantly enhanced by the use of a butt plug or other anally inserted item during sexual activity. It is typical for a man to not reach orgasm as a receptive partner solely from anal sex.

Some women also engage in anal masturbation. Alfred Kinsey in "Sexual Behavior in the Human Female" documented that "There still [are] other masturbatory techniques which were regularly or occasionally employed by some 11 percent of the females in the sample ... enemas, and other anal insertions, ... were employed."

Enemas can be used as a form of anal masturbation, as noted above by Kinsey, sexual arousal by enemas being known as klismaphilia, but also, enemas or anal douches can, for hygienic reasons, be taken prior to anal masturbation if desired.

Autosodomy is the penetration of one's own anus with their own penis. This is possible if the penis is long enough and the genitals are properly maneuvered.

Insertion of foreign objects into the anus is not without dangers. Unsafe anal masturbation methods cause harm and a potential trip to the hospital emergency room. However, anal masturbation can be carried out in greater safety by ensuring that the bowel is emptied before beginning, the anus and rectum are sufficiently lubricated and relaxed throughout, and the inserted object is not of too great a size.

Some anal stimulators are purposely ribbed or have a wave pattern in order to enhance pleasure and simulate intercourse. Stimulating the rectum with a rough-edged object or a finger (for the purposes of medically stimulating a bowel movement or other reasons) may lead to rectum wall tearing, especially if the fingernail is left untrimmed. Vegetables have rough edges and may have microorganisms on the surface, and thus could lead to infection if not sanitized before use.