She sees that you are watching her and decides to play a JOI game with you. Sarah strips down to nothing but her panties and starts doing yoga poses while you focus in on her panty covered crotch. She squats down with both feet together and her legs spread, slowly opening and closing her legs. She knows you are watching and it turns her on.
Sarah takes special care not to let the panties ride up or bunch because she loves the smooth way it feels against her skin.
At the very end of the video, Sarah pulls her panties down to her ankles and show me her pussy, then hold her feet up in the air stretching the panties between them at the camera as she encourages you to finish.