CNN’s Don Lemon appears to have figured out how to tell when President Donald Trump is feeling the heat.

The “CNN Tonight” host on Thursday noted how Trump often turns from side to side when giving interviews under pressure.

“When he does this thing, you know something is about to happen. This thing,” said Lemon, mimicking the movement.

Lemon’s analysis of Trump’s body language came as he called out the president for backtracking on his claim that Mexico would pay for the U.S. southern border wall.

Trump now denies he said Mexico would pay directly for the wall, but as Lemon noted the promise appeared on the campaign website.

Check out the full clip here: