I've had anal sex a few times with a couple of women, and I've met quite a few women who enjoyed anal sex but didn't want to try it with me because of my girth. I enjoyed anal sex because it felt different, hotter and tighter, and because my partners obviously enjoyed it. My first time, the sensation of heat struck me more than anything else.
One thing that worked with both women was to start with a lot of arousing, move to vaginal intercourse for a while, and then to anal. These women were both experienced so they knew how to do anal, but that sequence really worked well and it was easy penetration, totally pain free despite my size. When penetration is easy and pain free, and sex feels different and better, then why not anal?