Key West Trip With Friends

This past weekend I had a chance to go to Key West for the first time. There were five of us, 2 couples and me in 2 different rooms. I was the "Old Man" here, and the odd person without a significant other. The 3 of us in the 1 room were my best friend and her boyfriend. She is fairly conservative around me unless she has been drinking a bit. This is a newer boyfriend for her, and their first trip together. It was my trip, that they happened to tag along on. We had a blast!! We took in the sights, but mostly ate and drank in all of the long standing Key West bars. On our second night there, we were out hitting all the best spots including 1 of the strip clubs, and the bar that is clothing optional. It was cold that evening, so there were few naked people up there. It might have been us too, if it wasn't so cold. At the end of the night everyone returned to their rooms, and I had a feeling it was going to be interesting in my room that evening. I had no delusions of a threesome, but thought I could be a voyeur on their enjoyment. My friend is a dozen years younger, blonde, beautiful firm breasts (36C's), and just beautiful. Her boyfriend is younger than her and is a bit on the thin side. I sleep naked, but for their comfort I waited to drop my shorts and take off my shirt after I was in bed. All was quiet, and I started to drift off to sleep, but then I heard a little rustling in the bed next to me. At first it sounded like they were just adjusting to get comfortable, so I discreetly rolled over in my bed to face toward them. They were covered, but I distinctly heard the unmistakeable sound of a girl sucking on a penis. In the dark, I could slowly see her head bobbing up and down, and there were discreet slurping sounds. They were doing their best to be quiet, but being a little drunk, they probably didn't get how loud they were. By this time, my cock was at full mast, and I was just mesmerized by the sight and sounds in front of me. I was just kind of massaging my balls, and stroking slowly under the covers. They moved positions, and I could hear kissing and quiet moans from both of them. I could hear him start to finger her pussy with the in and out movement, but then it was quiet again for a bit. I hoped they had not passed out, but then I heard a faint moan of extasy, and I knew he was in her. I could see the motion in the dark of him pumping his cock in and out of her. I was too horny to not keep watching and stroking my cock. I don't think they were watching me at all, but I didn't care. I pulled the sheets down and was openly stroking my cock watching and listening to them. I slowed wanting to keep this going as long as they were going. They were still trying to be quiet, and they either forgot I was there, or didn't care. It was incredible to watch and listen as they were fucking away. I lasted as long as I could, but my cock just exploded with ropes of cum. The first was so powerful, it hit my neck. My whole upper torso was covered in cum!! I just layed there covered in cum until they were about done. I discreetly wiped off myself with the shirt I had there, covered up, and went to sleep. I can't wait for our next trip.