Her stepdaughter likes having her feet kissed
Believing that his life was incomplete because he had not completed the cycle of procreating someone who would take his genes to the next level was great stupidity. Since the world is full of stories of adopted children who do very well because of their last name. Then he adopts a girl who seems to have turned out better than having procreated anyone. And her stepdaughter likes having her feet kissed. This, while she is naked and with her legs open. Then he gives her a cock suck and can fuck her pussy. Which is great for any stepdad who has to support a girl who isn’t his blood.