Dear Jen,
I have recently discovered that I love rim jobs, both giving and receiving them. I know this isn't that bizarre of a fetish since it's commonplace in the gay  community, but as a straight male, I'm having a difficult time finding a woman who doesn't find it disgusting.  I even shave down there and only consider doing it after taking a shower. I've also taken the scientific route, explaining that the male orgasm comes from the anus and so on, yet, no matter what I try, I can't seem to get anyone to try it.  How can I convince them?
- The Lonely Hole

Dear Lonely,
Leave it to the human being to evolve into a species that's terrified of its own butthole.  

For the rest of the animal kingdom, it's the doorbell to the soul, the place where friends are made, enemies are sniffed out, and love is sparked.  But not for we the people.  We lock it away where the sun don't shine, take its name in vain every time we get behind the wheel of a car, and many of us prance around like we don't have one on the bottom of us at all!  After all the butthole does for us, this is the thanks it gets.  Makes me sad, it really does. 

You are one of the rare few who understands what a great gift it is, with its thousands of nerve endings and prostate party just up the road.  You and the majority of the gay male community.  By the way, do you have any idea how.....surreal it is to hear a straight dude taking comfort in the fact that his sexual fetishes are the same as the gay boys'?  Most men would watch a football marathon for days, weeks, years - however long it took to erase any fagalicious thoughts from their brains.  You are refreshingly secure in yourself and very highly evolved.  You should be proud.

Anyway, the reason gay men are so free about their buttholes is because gay men are so free about their buttholes.   It's one of the most popular items on their sexual menus and a heartily accepted part of their culture.  Straight male culture, on the other hand, has been trained to distrust its butthole, and the area is often quarantined during the act of sex (talking about it in regards to the act of pooping, however, is a whole different story). The situation is so dire, that should a lady with a curious pinky venture into the tunnel of shame, she risks getting it clenched off at the knuckle, without any explanation beyond, "move along ma'am, there's nothing to see here." 

Unfortunately, this smear campaign has been very effective in turning off both men and women to the man butt, and anal enthusiasts everywhere are suffering for it.  This is why you, and brave others like you, need to launch campaigns of your own to rewire the way straight culture perceives itself.  Continue to present your fabulous pink winker to the ladies, and hopefully you'll find a girl who's into it, and if not, you'll get those who aren't into it thinking about why they're not.   And about how you are.  And begin the eekingly slow process of erasing the many prejudices around it.  Future fans of the fanny will thank you.

As with all grassroots operations, you're going to need to be patient.  I'm not talking about waiting until popular opinion changes and the ladies are lining up outside your door with their tongues sticking out.  But as far as your personal life is concerned, you need to give the less-than-psyched lady time to warm up to the idea.  Let her know how important it is to you, how you get it all dressed up for the occasion, and then leave it alone.  Nagging.  Is there anything less sexy?

Instead, show her that you're willing to step outside your comfort zone to please her.  Be an attentive, fun, and adventurous lover whom she trusts.  Once she is comfortable with you, ask her to do things like fondle your butthole with her fingers or play with it using a vibrator with a rubber tickler on top.  Once she sees how much pleasure it gives you, if she really likes you, she may just do a face plant after all.  Or not.  If not, I'm afraid there really isn't a whole lot you can do other than focus on the other perks of your relationship and try to find things that both of you find really hot.

But don't despair, this is a very viable option.  As you said, you only recently discovered how much you love having your butt licked.   Lord only knows what other undiscovered delights are out there.