This Island Earth (1955)

None. However, two characters discuss a previous encounter, i.e. a midnight swim in a river. This episode allegedly took place entirely off-camera and in the narrative's past. The recollections of this incident are highly ambiguous. No viewer can be absolutely sure that these two characters actually did more than talk about swimming in a river. This is entirely within the prescriptions of the Motion Picture Production Code, which was still in effect when this film was made and released.

The alien ship's officers and crew, and the leading man and lady while they are aboard the alien vessel and on the alien world, wear loose-fitting jump suits showing no flesh other than the face and hands. These are clearly intended to allow freedom of movement only. (In fact, they strongly resemble the unisex jump suits that Mao Tse-tung encouraged his people to wear after taking power in what he named the People's Republic of China.)

One woman wears a dress revealing her shoulders and minor cleavage. In the next scene she is wearing a shirt revealing cleavage. Other than that, the dresses come down either to the ankle or halfway below the knee and don't reveal cleavage. The men wear business suits that reveal no flesh beyond the face and hands. (The leading man does loosen his necktie in a brief scene. This happens during a hazardous passage that produces intense, indeed oppressive, heat that the ship's air-conditioning system cannot handle. But the setting is *not* intimate, nor intended to be.)