Quickie with my mother-in-law before the wife arrives

I've been making out with her for a long time now when my wife is away. She's the biggest turn-on, looking wonderful with little lingerie marks all over her body and, on top of that, she engages in anal sex, something that my wife doesn't do at all. That's why every time we're alone at home, I feel tempted to eat her ass and it always ends up having anal sex that makes me cum a lot on her delicious ass...