Fucking my GFs sister Awlivv

I picked my GFs sister Liv up from the airport because she was too busy at work, again... Liv had decided to take a nap when we got home. I was just sitting there when she started to sleep rub rub my cock! I thought it was an accident, but she started doing it again when I woke her up. I just want her to be comfortable and I don't see how this is any different than us getting coffee? ???? I figured we could find out what else she had been dreaming about... ????