Sister helps me to learn control with edging session

My sister and I are home alone while our parents are away. We are both so bored, and I have been taking advantage of no parents to watch a lot of porn. My sister, Delilah, comes over and starts talking about being bored and horny, and soon she gets around to saying that she wants to watch me jerk off. The sight of my hard cock gets her going even further. She has always been sweet and been there for me, but I never expected she would do this.