Lets face it guys, there are lots of girls out there who don't like anal
sex, or won't even try it. There have been lots of taboos over the years about it, and girls these days are opening up to it more, but if your girl isn't in to it, then you'll need to be sneaky about it. Don't look too eager and don't get angry if she's not receptive.
Bring it Up Casually
Step one to getting your girl to let you put it in the backdoor, is to bring up the subject casually, or joke about it. This establishes the idea in her head. Make a joke, or tell an annectdote about anal sex around her and gauge her response. You can tell the story about how your friend's girl said they could try it, but he had to run to the store because they didn't have any condoms, but it was closed (and how he was banging on the door at midnight). Or the one about the article you read that said women who have any also have more orgasms, here
If She's Tried It Before
Sometimes just bringing it up will be enough ..→