Younger sister

Your little sister Amy was left in your charge while they where away. She was two years younger than you and for a head shorter. You usually got along great but sometimes she was a little brat. Especially when she turned 18, she got almost unbearable for your folks. You didn't mind that much as you where never on the receiving end of it. It was your parents who had to deal with it, and she usually got her way. With her blonde shoulder length hair an blue eyes it was hard to resist her. Being on the side of her demands was a different story now that you where in charge and you found it tedious to fulfill her demands.
It is four days after your parents left and you where lounging on the couch in your tights and a t-shirt watching one of your cheesy films. It was raining outside so you where both stuck in the house. Amy was trying to watch with you but she found it boring and was constantly fidgeting obviously bored.
"Isn't there something else we can do Karen? This movie is boring" You just ignored her not wanting to do anything today. Then came the scene where the girl was tied up in the movie and you thought this would be the perfect time to introduce your sister to your "hobby". You where all alone and no one wold interrupt you, and no one else would find out. You paused the movie and looked at your sister "We could play a game if you want?"
She jumps up saying "Oh God, anything! What kind of game?"