Every night, my sister's daily routine is masturbating with a vibrator! I was watching her do it, and then secretly inserted the vibrator while she was asleep. Seeing her writhing form, I couldn't hold back and put my dick in, and the vibrations increased the pleasure, causing me to cum inside...! Then, when my sister woke up, she demanded that I keep the vibrator inserted and continue thrusting, and she couldn't stop convulsing and orgasming, making me cum inside her over and over again!? The fierce thrusts of my dick and the vibrator going wild inside her vagina seemed to have destroyed my sister's pleasure center, causing her to orgasm wildly!
