Not only was the gorgeous Heddy naked but writhing in ecstasy, hence the title. The movie's love scene (for those who don't want to watch the film all the way through, and you know who you are) starts at 45:32. You would miss a lot fast forwarding though.
The entire movie is rather entertaining (if largely silent). It revolves around a beautiful young woman who marries a much older, impotent husband. On their wedding night, she hopes to have sex, apparently he doesn't (or can't). Our young heroine soon becomes very depressed (as many would) and longs for erotic fulfillment. She finds it in form of a gorgeous (we're talking major man candy here) young officer. The movie has a sensuous, languid feel. Scenes take a long time to build, and the actors convey most of their emotions through their faces. Interestingly, the first female orgasm seems to take place through oral sex.
The movie's content (skinny dipping, adultery, sexually frustrated women, and implied cunnilingus) created an avalanche of controversy, leading to its tagline of "The Most Talked About Picture in the World". It was banned in the U.S and was one of the factors leading to the infamous Hays Code that basically stripped sex from American cinema for about 30 years. Here is the entire move.
Happy Valentine's Day xoxo!