More usually an admonishment to fidgeting children, the above command should be directed with equal force to excessively mobile interviewees.
The trouble with TV interviews is that they cannot cope with distractions. The focus of most TV interviews should be on what is being said, not on what is being seen. Yet too often the behaviour and body language of the interviewee drags the audience’s attention away from the all-important conversation that is taking place.
It is not easy to remain calm and still, under the glare of the camera and the scrutiny of a very large audience. But I have sat opposite too many interviewees who swivel in their chair, switch from buttock to buttock (and back again) or throw their head nervously from side to side. Some, indeed, have attempted to do all three.
Keeping relatively still should be on your must-do list when tackling any interview. Make yourself comfortable before the interview starts. Are you going to cross your legs? Are you going to lean forward or sit back? How are you going to use your hands?
The best advice is, behave naturally. That can include hand gestures, as long as they are not repetitive, or obscuring your face. And of course nobody expects you to remain totally static through an interview. Move naturally, but not excessively.
For a child, fidgeting is usually a sign of boredom – definitely not the impression you want to leave with your TV audience.