TO audition for “Basic Instinct,” Sharon Stone wore an Armani pantsuit and a sheer blouse with no bra underneath just to show she had no problem with nudity, she told her Hamptons Film Festival fans at the Bay Theater in Sag Harbor. Stone had campaigned eight months for the 1992 role after her manager stole the script from a secretary’s desk. “After 12 actresses turned down the role, it was finally mine,” Stone recalled. She certainly proved she wasn’t shy when Paul Verhoeven filmed her leg-crossing scene. But Stone said she was shocked at the first preview, when the audience gasped. “After a week of considering to stop the release of the movie, I decided it fit the character in the film and it should stay in.”