Step Daughter Loves It When I Drill Her Tiny Asshole

My step daughter loves it when I drill her tiny ass. I know she's only eighteen years old, but she's been taking it up the ass for the last year. I started out slow, with just a finger or two, but now she's begging for me to use a toy. I have to be careful with my speed because I know she's still tender after her last trip to the emergency room.