I have a really hot sister, Alex, who is 16. She has a very sexy curvy body, with great tits and a nice ass. For the past 3 years, I have been masturbating with her panties, sometimes clean ones from her drawer, and sometimes worn ones from the basket.
I think she masturbates sometimes herself, and I love it when I can smell and taste her sweet pussy juices on the panties. She wears mainly thongs now, and has some really sexy ones, with matching bras.
I fantasise about having sex with Alex when I'm wanking into her thongs, and when I cum all over them, I imagine she is wearing them and I'm cumming all over her, or deep inside her juicy wet pussy! I don't know what she would say if she ever found out, maybe we could masturbate together!