Tips for having sex without a condom?

I've been in a long term relationship for 2 years, we've both been tested for everything and we're both clean. I've never had sex without a condom and I'd like to try it at least once. We're not looking to conceive yet so I'd like to avoid pregnancy -- I'm just wondering if anyone has any tips/suggestions? The pull-out method seems to risky, is plan B bad for you if you take it once? Should I just get on birth control? Is it worth it to try?