This story is entirely true, with a few minor details modified to protect the guilty and to move the story along. I try to stick to the facts of what happened as much as possible, which means that it might not be as "hot" as some fictional stories - my apologies in advance. The events took place a little less than nine years ago now, in the spring of 2000.
The first threesome I had came when I was a sophomore in college. I had a girlfriend at the time, but it was a long distance relationship in the process of falling apart. We had agreed that it was an "open" relationship and we could have sex with other people (I didn't have any real problem with this, and initially neither did she, but eventually she started getting serious with one of the guys she was fucking, and that was the end of "us" - although we did hook up a couple of times even after we broke up). I started looking around online and shelled out some money for a membership to a swinger's site. Initially I didn't have much luck, but after a few weeks I got a response from a couple that was looking for a threesome partner.
We chatted on IM for a few days to get to know each other and eventually set up a time to meet. We were about 45 minutes away from each other, so I drove up their location. When I got to their house they were having some beers and watching some porn, waiting for me to arrive. She was a hot little number - about 5'4" or so, thin, dirty blonde hair, and a large B or small C cup. He was ex-military - had a bit of a beer belly but still had the muscles. She was in her mid-twenties, he in his early 30s. All three of us sat down on their couch and made a little small talk, had another beer, etc.