That is,to be restless and unable to sit still.

VOA: special.2009.06.28

Or, if you're a pediatrician with a really small patient who will not sit still, it's because the laws of quantum mechanics don't allow an object to have a definite position and momentum.

或者你是个儿科医生,而你的小病人却总也坐不住,这是因为量子力学,不允许物体同时具有确定的位置和动量

耶鲁公开课 - 基础物理课程节选

And once he said: "Four-fifths of our troubles in this life would disappear if we would only sit down and keep still."

VOA: special.2010.12.23