I gave my annoying sister-in-law an aphrodisiac, but it worked better than I expected, and her legs shook → she orgasmed with her legs pinned at a right angle of 90 degrees! My parents remarried and I got a beautiful sister-in-law, but she was a jerk who made fun of me and looked down on me! I couldn't stand being mocked every day! To get revenge on my sister-in-law, I put an aphrodisiac in her drink... it worked so well that her legs were shaking so much that she couldn't stand up! Not wanting to miss this opportunity, I played with her body, made my sister-in-law feel good, and inserted my dick! This time, she got so excited that she orgasmed with her legs pinned at a right angle of 90 degrees, and it was the best revenge!