Snape pulled out his wand from an inside pocket of his robes and Harry tensed in his chair, but Snape merely raised the wand to his temple and placed its tip into the greasy roots of his hair.
Muscles are burning energy being tensed and ready to go to work, which is generating heat, so the body moderates its temperature by sweating, even when you feel cold.
And he swung open the door and we stepped inside, and we were hit with this overpowering smell and every muscle in my body tensed up and I coughed and my eyes teared.