The Princess

Once upon a time there lived a king. The king had a beautiful daughter, the Princess. But there was a problem. Everything the princess touched would melt. No matter what; metal, wood, stone, anything she touched would melt. Because of this, men were afraid of her. Nobody would dare marry her. The king despaired. What could he do to help his daughter? He consulted his wizards and magicians. One wizard told the king, "If your daughter touches one thing that does not melt in her hands, she will be cured." The king was overjoyed and came up with a plan. The next day, he held a competition. Any man that could bring his daughter an object that would not melt would marry her and inherit the king's wealth.
THREE YOUNG PRINCES TOOK UP THE CHALLENGE.
The first brought a sword of the finest steel. But alas, when the princess touched it, it melted. The prince went away sadly.
The second prince brought diamonds. He thought diamonds are the hardest substance in the world and would not melt. But alas, once the princess touched them, they melted. He too was sent away disappointed.
The third prince approached. He told the princess, "Put your hand in my pocket and feel what is in there." The princess did as she was told, though she turned red. She felt something hard. She held it in her hand. And it did not melt!!!
The king was overjoyed. Everybody in the kingdom was overjoyed. And the third prince married the princess and they both lived happily ever after.
Question: What was in the prince's pants?
M&M's of course. They melt in your mouth, not in your hand.
What were you thinking??