Sharon Stone Says She Was Tricked into 'Basic Instinct' Explicit Shot

Sharon Stone's finally calling out the underhanded move that got her out of her underwear for the infamous cross-legged scene of "Basic Instinct" ... and says the experience was humiliating.

Sharon claims someone on the production team told her she needed to take her panties off for filming because the white color was reflecting the light. She says they ensured her "we can't see anything," referring to her private parts.

However, according to Stone's new memoir, "The Beauty of Living Twice," when she screened the final cut of the movie in a "room full of agents and lawyers, most of whom had nothing to do with the project" ... she realized she'd been double-crossed, if you will.

Sharon says she slapped the film's director, Paul Verhoeven, after the meeting and called her lawyer, Marty Singer, who told her what went down was against SAG policy and the movie could not be released without her approval.

However, Stone says she thought about it and ultimately decided to allow the scene to be included because it fit her character ... but it didn't change the duplicity of the situation.

Stone also alleges she's dealt with sexual misconduct on sets for years, including a director who demanded she sit on his lap and a producer telling her she should have sex with her co-star to increase on-screen chemistry.