2. A lame reason people give for cheating on their significant other.
2. "Baby...it wasn't my fault I slept with your sister...I'm a sex addict...I can't help it.."
also, commonly known among teenagers as "a krystal".
Example; "I was wrong for cheating on you. I was pulling a krystal, and i'm sorry".
-my exgirlfriend krystal is such a sex addict. i swere, she used to try and pressure me into threesomes with her and some random person. it was just plain sick.
-You can't live without sex for a day! your such a damn sex addict! i can't believe you.