Inner Party Romance can be a touchy subject for a lot of gaming groups and with the wrong group of players, it can be disastrous in real life, as well. It's important to tread lightly when approaching romantic encounters in game, but with a little maturity on the part of the players, it can be fun and rewarding.
First of all, make sure everyone is comfortable with the idea. It's all too easy for a romantic scene to devolve into sex jokes, and you need to be sure that everyone is on board. Speak to your GM first, and get their opinion on whether or not what you're imagining will work with your particular group. The GM can also help you work out what to do (and you might give them a few ideas for a story hook, too).
When the opportunity arises in game, be mature yourself. There's no need to go overboard with detail when a few light details will suffice. Until you're absolutely sure everyone is comfortable, it's best to avoid getting hot and heavy. Quite a few people won't speak up if they're uncomfortable with that level of detail, so it's really for the good of the group to make any description brief and gloss over the finer points.
On the other hand, if your group is up for it, some serious romance can be quite fun. Your campaigns can benefit from all sorts of romantic entanglements to liven up the story and give your characters a little more depth.