While not exactly mainstream, anal sex has become less taboo as society has had more open discussions about sexual pleasuring in recent decades. Depending on the research study, anywhere from 6% to 40% of people report having ever engaged in anal intercourse, with up to 10% of heterosexuals reporting at least one anal sex session in the last year. So there are plenty of couples who are at least curious to learn more about anal pleasuring, and that’s actually the best place to start.
In sharing your curiosity to explore anal sex, introduce the idea of anal play, in general, as a possible source of pleasure. This can involve stimulating the anal area of either partner with your hands, a sex toy or tongue, sans any penetration. Doing such, especially with lube, can help you to test the waters as to whether this is a hot spot for either of you. It also helps to prepare the anal opening for penetration, should one or both of you ever want to be penetrated.
One effective, sexy way to introduce anal pleasuring is to highlight this oft-featured section of “Touch Me There! A Hands-On Guide to Your Orgasmic Hot Spots,” a book on sexual pleasuring. Ask your partner for her thoughts on anal play and if she has ever thought about “going there.” Alternatively, point to examples in erotica, for example, if the two of you ever watch porn or read a novelette together, and let her know that you find anal sex a turn on, highlighting why it makes you hot or curious. Both of these tactics invite a safe space for sharing without pressuring your partner, which may cause her to sexually shut down.
If either of you are ever up for penetration, make sure that you’re in a relaxed space and prepare the anal sphincter muscle so that the action is comfortable. This involves engaging in a lot of foreplay to warm up the groin and anal areas, while staying relaxed by releasing any tension in the buttocks. Using plenty of lube, begin with finger penetration to relax the anal sphincter muscle. Breathe deeply and communicate before deepening digital penetration. Stop anytime pain is felt, slowly pulling out if need be. Basically, seek to get the anal opening stimulated before attempting any penetration with a penis or anal sex toy. This may happen during one sex session or may take several attempts over the course of many sex dates, which is perfectly fine. For more information on safe, effective ways to have anal sex, check out Tristan Taormino's "Expert Guide to Anal Sex."
Best of luck in your efforts!