Modesty Leaves

Modesty Leaves are a way to cover the naughty bits while still leaving a primal feel to a scene, or alternatively because they're the only thing available to cover the genitals.

This trope comes from the original Adam and Eve Plot: after they ate from the tree of the knowledge of good and evil, and became aware that their nakedness is totes taboo, they covered themselves with fig leaves. Also, snakes. This makes the trope Older Than Dirt. Modern people, of course, are more likely to use Fur Bikinis instead.

This trope gets a lot of coverage in art, especially of pagan subjects that would have been naked in earlier depictions but needed to be somehow clothed for modern moral guardians.

A portable version of Scenery Censor. Compate Godiva Hair.

Music

 * The Yatta! video of ancient meme status has five grown men in leaf-covered loincloths.

Myths and Legends

 * Adam and Eve from The Bible, obviously.

Visual Art

 * In many religious paintings, including Domenichino's The Rebuke of Adam and Eve. (NSFW if your work hates art.)