Azula wasted no time tying Naruto to a tree. Once he was securely tied down. She slapped him awake. Naruto opened his eyes and groaned.
"Now let's try that again." She says. "I'm going to ask you if you're an airbender and if you deny it, I'm going to make you suffer."
"I really have no idea what an airbender is" Naruto insisted.
"Wrong choice." Azula says coldly. She considered how best to torture him. Fire would be too volatile to use. She needed him able to answer questions. She thought about all the miles she spent walking today and how she didn't need an uncooperative. Suddenly she had the perfect torture in mind. Slowly she began to take off her boots. Naruto watched her pretty bare feet appear in front of him.
"What are you doing?" he asked.
"I've figured the perfect way to torture you." Azula told him. "By the time I'm done with you, you'll be begging me to stop."

What does she do to him?