The act of regulating your body
temperature in the cold or heat while sleeping using one leg or foot.
For example: If you are too hot under your blankets, you stick a leg/foot out from beneath the blanket allowing you to cool off without having to give up the warmth of your bed.
Reverse example: If it is too cold, you can partially cover your body/leg/feet with a blanket to help warm
to the right temperature.