When I was nineteen years old, my younger sister, Lynnai, asked me to back up a story (lie) that she was going to tell my mom, as an excuse for why she had come home after curfew. I agreed to validate her story that she was at my place because I knew that my mom would misjudge the true situation, which was that my sister was at her boyfriend's house, and put her on punishment for her actions. Unfortunately, the truth materialized, and my mom became upset with me for vouching for Lynnai, So, I decided to explain to my mother our reasons for the "lie".