Eighteen-year-old Colin admits that he has molested his younger sister twice. In the video above from Friday's episode of Dr. Phil, he describes what happened during the incidents – and how it made him feel.

“Something told me, ‘Hey, this isn’t right. You shouldn’t be doing this. This is your sister,’” Colin says of the first incident. “It’s like the other half of my brain just said, ‘Oh, who cares? I want what I want, and I’m going to get what I want.’”

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Colin describes the second incident. "I had that uncontrollable desire for sex, and I was willing to do anything or hurt anybody to get it,” he admits.

WATCH: Teen Describes Being Molested By Her Brother On Two Occasions

Hear more from Colin in the video above, including why he has never completed a treatment program for sexual offenders. And on Friday's episode, Dr. Phil questions Colin about his behavior?. Does he have any remorse, and is he ready to change? Check here to see where you can watch.

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Teen Explains Molesting Sister Twice: ‘I Just Wanted My Needs Met’