I managed to spy on my sister this morning, she had just come out of the shower and was drying her self in her bedroom. I thought I had struck lucky and she was going to masturbate but it was literally just 5 seconds of vigorous clit rubbing with her middle finger.
god it was so hot, I jacked off immediately and spurted as much as I have ever spurted, it went on the carpet and I had to rub it in with my foot!