Lilli is in her room bending over as you walk in jerking off, she catches you and asks what you are doing but instead of insulting you she encourages you and offers to help. Calling you a pervert and how much she loves it. You both are alone right now so you let her do it. First she gives you jerk off instructions to get you very hard and encourages you. She starts sucking your cock and giving you a cum countdown. Being such a good lil sister for you.