Me and my first wife sister promise never to fuck each other but one night we all got drunk and my wife and her husband fell asleep totally passed out, we went downstairs in my bar room where I had a couch and we did this exact thing, just rub my cock on her ass cheeks while I lean down and kissed her as she turned around would kiss my mom feeling my cock rubbing her ass cheeks, her pussy was so wet and it made the end of my dick wet, my cock was right up against her ass and I slowly pushed as her eyes opened up and she said go ahead, ended up ass fucking her for a good 30 minutes