Anal masturbation is an erotic stimulation focusing on the anus and rectum. For humans, common methods of anal masturbation include manual stimulation of the anal opening, and the insertion of an object or objects such as fingers, tongue, phallic-shaped items, water play, or sex toys such as anal beads , butt plugs , dildos , vibrators , or specially designed prostate massagers. 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 healthy functioning of the smooth muscles surrounding the prostate , and of the pelvic floor muscles.