A term used to refer to the position one is residing in whilist "standing" and "laying" at the same time. It is very difficult to do this, and is purely dependent on an object to help you. One place you can stlay is on a bed where your feet can touch the ground and you can lay (on your back or front) at the same time.
Megan: What the hell is Colin doing ontop the hand-rail on the steps?
Eden: Oh, he's just stlaying.