I got tested about 6 or 8 months ago. First they ask you some questions about your history. How recently you've had sex, how many partners, ever had sex with a male, if you use protection, what diseases you're inocuated against, etc. They took a cotton swab and swabbed the tip of my penis (they didn't stick it right in there), looked closely for visible sores, pubic lice, etc. Then they gave me a little cup and I went to the bathroom, pissed in it (nobody watched or stood guard, this was a voluntary thing). Then gave it back to the nurse. She then took a little vial of blood and gave me a jelly bean.
Ten days later or so they called me back in there and told me the results. Everything was fine for me, and that was the end of it. If there's something wrong, if you test positive for something, they would have told me in person and then given me my options.
I hope that's detailed enough for you and that you aren't too nervous about goin. You should definately go and get tested, it's really not a big deal. It took me half an hour at the most.
With your next partner, she won't (or shouldn't) just trust that you're clean because you say so, and if she says she is, that's great, but wear protection anyway. If it becomes serious between you and her then get tested together. Getting tested doesn't mean you don't trust your partner, as an ex-girlfriend of mine thought. It means you want everything to be safe for the both of you
