A situation in which a character has only their anus (i.e. literally only their anus, or their anus but not their genitals) exposed. For example, a character may be wearing underwear with a cutout for the anus, or have full clothing on with a tear in the back that exposes their anus (i.e. easy_access). Alternatively, they could be fully nude with chastity, maebari, or some other means covering their genitals, possibly in bondage, so as to make only their anus accessible for viewing or sex. Also applicable to, often Japanese, cute-style art that's not explicitly pornographic where the artist included the character's anus (e.g. x_anus anus_only).