Oral sex or oral-genital sex means both mouth contact with the vagina, which is called cunnilingus, and mouth contact with the penis, which is called fellatio. Cunnilingus comes from a Latin word for vulva (a woman's exterior sex organs), cunnus, and from the Latin word for licking, lingere. Fellatio comes from the Latin word fellare, meaning to suck. There are many different kinds of oral sex techniques, and you've probably even picked up a set of oral sex tips or your own oral sex techniques along the way. Some of the more common oral sex tips involve both partners performing oral sex techniques at the same time.

Either form of oral sex can be done with one partner stimulating the other individually, or both partners can stimulate each other's genitals simultaneously. Oral sex given simultaneously is commonly called 69, or, the French translation, soixante-neuf. This is because the body position of a couple having mutual oral sex resembles the numeral 69.