[SSIS-019] Even if she is nearby, her little devil sister Sayaka Otohaku who makes me crazy with ear whisper nipple blame from behind

"I have to make sure I'm the right boyfriend for my sister!" One day, my sister brought her boyfriend home, but the impression including appearance is not good! "What's good about this guy?" I thought so, I decided to try various things and decide if it is an appropriate boyfriend! First of all, 360° around the nipple from behind and concentrate stimulation! And whisper a dirty word that seems to be able to relax the brain in the ear! And then... Faint in agony and ejaculate immediately! "It's the lowest thing to feel even if your sister is right next to you!" 」。