Final answer:
Oral sex performed simultaneously by two partners is known as sixty-nine, while cunnilingus, fellatio, and anilingus describe specific oral sex practices for one recipient. Cultural interpretations of sexual acts can differ, as evidenced by anthropologist studies.
Step-by-step explanation:
The term for oral sex that is performed simultaneously by two partners is called sixty-nine (option 1). Other terms listed, such as cunnilingus, fellatio, and anilingus, describe specific types of oral sex where only one partner is the recipient. It is important to be aware that sexual practices and their interpretations can vary greatly across cultures and historical contexts.
For example, anthropologist Gilbert Herdt's studies on the 'Sambia' highlight how in some societies, sexual acts can have ceremonial and ritualistic meanings, often leaving room for interpretation and controversy regarding consent and the categorization of such practices.