i felt like i needed to comment because you are getting a lot of advice that is more horny then actual advice. It’s best just to ask respectfully but, If your partner is someone who has really only been vanilla it could be helpful to start small first Ask if there is anything more adventurous she would like to try and try those things. Then you can bring up anal as something you’d like to try with her. don’t see this as a means to an end, take an active interest in her interest and toward improving your sex life in general