On top of my coprophobia, I have a very specific ideas about what is and what isn't romantic. First of all, it seems just awful to be on the receiving end. Despite what Sasha Grey films (which I have NEVER seen) imply, I have a hard time wrapping my mind around the idea that a visit to starfish alley is pleasant for the resident. Secondly, I understand that there is much gas involved in the post-coital process. While I understand that women have many of the same gastrointestinal functions as men, I prefer them in the abstract and relatively small doses. James Joyce, I am not. Finally, I want no part in whatever the quid pro quo for a situation like this is.
I'm sure your butt is terribly clean and that other dudes enjoy amateur proctocology for very good reasons. But the rest of us want nothing to do with any sewage treatment plant when there's a perfectly serviceable magical garden just across the way. The only thing I regret, outside of missing another weird human experience on Spaceship Earth, is that my reluctance has made one of my favorite jokes regarding the difference between peanut butter and jam (NSFW) seem hypocritical.
If you decide to give it a try, please use a lubricant that's not going to destroy your condoms, start very slowly and consider taking a decent multivitamin with your breakfast, you're not getting any younger.
*Note: Adam Carolla coined this term, please attribute when using. I came up with the more scatological Cadbury Cherry, which I'd prefer if you just forgot all about.