I actually saw someone else ask this question today, and it kind of stumped me. I couldn't think of any very good ways to parse the phrase into chinese. So I became curious if there is a pre-existing phrase I've never encountered, or what would be a good way to convey this concept. I thought of 他把站姿交換不安了, which still doesn't actually convey shifting weight (and isn't very good in my opinion).
EDIT FOR CLARITY: I am aware of a few phrases like 坐立不安 or 忐忑不安 to convey a similar sentiment. I am more interested in how one would convey the literal movement of shifting weight from one foot/side of the body to the other (as one does when uneasy/uncomfortable). Sorry for the confusion.