It is especially helpful in situations where glass, or water, or falling snow might make your other pants or shorts disappear. It prevents you from appearing naked.
The picture here shows it underneat the default garment in the previewer.
This is a layer of white underwear shorts with gold star pattern. It is meant to be worn under male garments like pants or shorts, to prevent the pants or shorts mesh to show the naked skin underneath.
It is especially helpful in situations where glass, or water, or falling snow might make your other pants or shorts disappear. It prevents you from appearing naked.
The picture here shows it underneat the default garment in the previewer.