Sextraterrestrials are only found in low-budget pornographic films. They usually look quite similar to human beings, with perhaps antennae or a tail. More often than not, they are female. Here are some other traits found in sextraterrestrials (note that there are a few different types):

• They must procreate with as many humans as possible to save their dying race.
• The only way they can stay alive in Earth's harsh environment is by refueling their "sex meters" every hour.
• They are intrigued by the human concept of love, and want to experience it firsthand.
• They are evil creatures who rape Earth women and impregnate them with alien seed.
• Women on their planet are not as beautiful/talented in bed/promiscuous as Earth women.
• They are on Earth looking for Earthling sex slaves.
• Their sex is usually more vigorous than Earth sex, and their orgasms are more powerful.

Sextraterrestrials are born when sci-fi fans think they can direct porn (or vice versa). Although the director may have grandiose plans, more often than not, the cheesy plot of sextraterrestrial-laden films more closely resembles paper-thin filler time between sex scenes than "The Star Wars of Sex".

As a plot device for porn, this is becoming as worn out as "The Pizza Guy."