When Narcissus looked at Echo he didn't see beauty. He saw a creature that had latched onto him. He could even say that her being around physically was a drain on him. He could stand it when she was just an idea, a thought, or a name. In the flesh it disgusted him.
"Don't act so nervous, it makes you twitchy." He took a seat beside her. If he were to get this over with now he might feel better about himself later.