Wiktionary
anal gland
n. (context anatomy English) A small paired sebaceous gland found near the anus in many mammals, secreting a liquid that is used for identification of members within the species.
Wikipedia
Anal gland
The anal glands or anal sacs are small glands found near the anus in many mammals, including dogs and cats. They are paired sacs located on either side of the anus between the external and internal sphincter muscles. Sebaceous glands within the lining secrete a liquid that is used for identification of members within a species. These sacs are found in all carnivora, including bears, sea otters and kinkajous.