So Sub1 has served Dom1 a long time. One day Dom1 gets a visitor from a much younger woman, Dom2. Sub1 answers door and Dom2 sneers something like "So you're the sub" without any more attention than that. Dom1 and Dom2 then have casual conversations, and then go to work on Sub1. I remember something hot about the Dom1 showing Dom2 how to anally fuck Sub1 with a very academic commentary about angle and approach. And then later, Dom2 beats Sub1's ass with a shoe. I know sounds crazy, but I thought it was hot. Ring any bells?