Anal-oral sex, also referred to or described as anal-oral contact or anilingus (from anus + lingus (Latin Lingere: to lick, less commonly spelled analingus), is a form of oral sex involving contact between the anus or perineum of one person and the mouth (lips) or tongue of another.

Oral is by the mouth

Anal is by the anus

anal

Minimal genital-genital contact can transmit chlamydia. Use a condom before oral, anal, or vaginal sex or genital-genital contact.

You can get chlamydia from oral, anal, or vaginal sex; from sharing sex toys; or from genital-genital contact. In addition, a baby can get chlamydia during birth to a woman who is infected. If none of these applies to you, you won't get chlamydia.