Rob Reiner demonstrated 'When Harry Met Sally' deli orgasm scene in front of his mother

The infamous deli scene from "When Harry Met Sally" required some direction that may have made director Rob Reiner blush.

In a 30th anniversary retrospective on the classic romantic comedy, Reiner and stars Meg Ryan and Billy Crystal reminisced on the scene, in which Ryan's Sally simulates an orgasm over lunch at Katz's Delicatessen with Crystal's Harry.

“We had the extras, the crew — a lot of people [in the deli while filming]," Reiner recalled to People. "My mother [Estelle Reiner] sitting there.”

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Meg Ryan and Billy Crystal star in "When Harry Met Sally." The film is celebrating its 30th anniversary this year.

Meg Ryan and Billy Crystal star in "When Harry Met Sally." The film is celebrating its 30th anniversary this year. (Castle Rock)

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“Rob kept giving me sounds, ‘More, aaauuuuhhnnnnnn!’ All in front of Estelle,” Ryan said of filming the iconic moment.

Estelle Reiner is the elderly woman in the scene who ended it with the famous line, “I’ll have what she’s having.”

That quip, Rob says, needs to be credited to Crystal.

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“Billy, he added the biggest laugh in the movie, which is the biggest laugh in any movie I’ve ever been involved with,” Reiner gushed. “‘I’ll have what she’s having.’ My mother says that line.”