You like to watch your big sister in her bra and knickers, applying her lipstick, but she has had enough of you always sneaking around and perving on her. She tells you to leave but you refuse, saying you just love her mature body so much. After what happened last time, she is worried you'll get too worked up again and take things too far. She reluctantly says you can masturbate, and that she will touch it once and then you have to go. But she admits that it feels nice having your dick back in her hand again, and takes off her bra and wanks you off till you cum and she rubs it all into her breasts.