You and your step-Mother have a tradition. Whenever you and your wife come to visit, she sneaks at night and fucks you next to your snoring wife. The risk turns you both on so much. Knowing she could wake up at any moment and find you fucking your own step-mother. step-Mommy rides you while you both try to stay quiet, and you tell step-mommy how much hotter she is than your wife. The bed is rocking, and you're both moaning, the most dangerous fuck of your lives, if people knew your forbidden secret. The riskier the better (POV style, no visible penetration)