The legendary actor, 67, who plays Ben Stiller's dad in the film, says his favourite moment was rubbing cream all over his co-star's busty chest before nuzzling his face in them.
Hoffman said he wanted to make the audience believe that Streisand, who plays his sex therapist wife in the sequel to 'Meet The Parents', were a real married couple.
He told Britain's Independent newspaper: "I whispered to Barbra in once scene, 'Your breasts look great today'. She loved it. She loves her breasts."
Meanwhile, Dustin has confessed he terrorised his other co-star Robert De Niro - with an electric fart machine.
The two-time Oscar-winning actor says he ruined 100's of takes for the 'Godfellas' star by setting off the crude contraption whenever he was filming, and admits he was amazed by the machine.
He told Britain's Radio 2: "De Niro had the most trouble with it. It was a prop man who gave it to me. It was a revelation for me, because I come from an older generation than the prop man and the fart bags I'm used to you had to inflate them yourself."