Hands as Costume
When hands are used as a covering of the pelvis they are classified as a species of culotte. This is similar to the hands-on-breasts soutien-gorge.
Hands, of course, are organic elements, and unlike costumes made of cloth or other material they present a much more fluid motif of coverage.
When the subject is wearing a top, coverage is easy (JE9026). The major choice is which hand to use, or both. Many of these poses are classics, such as the famous "September Morn" (SM1310). Hands also provide a second layer of coverage for subjects who are scantily attired, but otherwise clothed (JE9025).
When the subject is topless and otherwise nude, she must make more difficult choices. These include using one arm and hand to cover the breasts while the other is used to block the pubis (JE9169A), or leaving both breasts bare and covering the pelvis with both hands (JE9213). These too are classic poses, many of which are "caught unawares" poses (VP5E10). Desmond Morris is but one sociologist who has explored these reactions to modesty.
Occasionally hands are also used to augment coverage of the behind, especially when the subject becomes self-conscious about exposing too much of it (NY9810). As with hands in general, this coverage also has symmetries (RD8740A).
Closely Related Species
Hands over the crotch or buttocks is to the culotte as hands-on-breasts is to the soutien-gorge.
The moving of the hands to reveal the pubis and/or buttocks takes the bikiniite into the realm of the bottomless.