Vanity 6 was a female trio Prince put together to showcase his girlfriend, Denise Matthews. The pair met at the American Music Awards in 1980 and began dating. A Canadian who made her way to Los Angeles, Matthews was a model, not a singer. This didn't deter Prince, since for what he had in mind, the look was more important than the sound.
Prince named Matthews "Vanity" (he wanted to name her "Vagina" and pronounce it "Va-jeana," but she nixed the idea) and teamed her up with two of his other female associates, Brenda Bennett and Susan Moonsie, to form the group. Using his associated group The Time as backing musicians, Prince produced their self-titled album, which was released in 1982. "Nasty Girl" was released as a single and made #101 in America. The group opened for Prince on his tour later that year, performing a short set while wearing lingerie.
This song is clearly about sex, with the girls playing coy to lure a man into their little nasty world. In the end, they're disappointed, as his love doesn't last. "Wake me when you're done," they tell him. "I guess you'll be the only one having fun."
The spoken interlude on this song represents the lovemaking, although it also relates to dancing. After all, it could be a 7-inch record she needs.
Prince put the Vanity 6 project together in the spring and summer of 1982, after he finished touring for his fourth album, Controversy. During this time, he also worked on his 1999 album and oversaw the second album by The Time, What Time Is It?
"Nasty Girl" is in line with what Prince was doing at the time, with extremely sexual lyrics and smooth funk beats.
After the Vanity 6 album was released, Prince and Vanity had a falling out and he replaced her with Apollonia - another one-named protégé - and re-named them Apollonia 6. He also gave Apollonia the female lead in his movie Purple Rain, which was originally Vanity's role. Vanity eventually became a born-again Christian, and renounced the highly sexual nature of her early work. She died in 2016, two months before Prince passed away. Both were 57 when they died.
Beyoncé performed part of this song on her 2016 Formation tour as part of a tribute to Prince.