A "texas Star" is defined as a single woman with at least two men dual penetrating her, while each hand masturbates another man or woman and she orally pleasures a fifth.
It is named after the 'Texas Ranger' star, which has 5 points, with a nodule at each point. Traditionally a Texas Star will be one woman and five men, but other gender combinations are considered valid as well.
Other combinations are also considered valid texas stars, sometimes with a male at the center having sex, oral anal or vaginal, while he is being penetrated anally. The only consistant factor is that traditionally there are 5-6 people in simultaneous intercourse with one person.
Texas stars are common in pornographic movies, and are often used to depict gang bangs
Quote from "I will fear no evil" by Robert A. Heinlein-
"(Oh, of course, twin-except that Joe let them watch every brush stroke, once Gigi was sure you didn't mind. Say, Joan,
Gigi would go for a Texas Star with Anton and Fred, I feel certain. And Joe
would go along; he likes them. What do you think? Easy way to keep your
promise to them, huh?)"