My sister masturbates with a vibrator every night! I was watching her and secretly inserted a vibrator into her while she was sleeping! I couldn't resist watching her do yoga, so I inserted my dick, and the vibrations made me feel even more pleasure and I came inside her...! Then my sister woke up and asked me to piston her again with the vibrator still inside her, and she couldn't stop spasming and cumming, feeling the double insertion of the vibrator and dick and cumming over and over again! And I came inside her over and over again! To be honest, the sight of my sister getting completely addicted to the deep vaginal orgasms she had never experienced was extremely erotic!