I used to DJ back in the 90's, raves and clubs. At a big New Year's Eve party at a convention center (at least 6000 people there) I met a cute little girl after my set and we found the way up to the catwalk that took us out over the floor of the rave, about 6 stories up at least. We started making out, then she dropped to her knees, took my cock out and sucked me off for a couple of minutes. Then she stood up, kissed me and asked me to fuck her from behind while she bent over the railing and watched the party below us. She bent over, grabbed her panties with one hand to pull them aside as she grabbed my cock with the other and guide me into her pussy. She turned around to look at me, and said "fuck me hard", so I did my best to hammer her as deep and hard as possible. When I was about to come I pulled out and shot my load over the edge of the catwalk and down into the crowd below. In retrospect it wasn't a very nice thing to do to the people dancing below but at the time it was hot.
I also had sex standing up in a club DJ booth just before I was getting ready to play, this hot girl was hanging with a few of us and kept smiling at me. While my buddy was spinning, she came over to say hi, introduce herself and then tell me that she thought I was very attractive. I smiled and told her how attractive she was, then she laughed and gave me a hug and a quick kiss on the lips. Then she took my hand in hers, and we just hung out making small talk for a bit, listening to my friend DJ. Then she leaned in close, kissed me on the ear and whispered that she really wanted to kiss me but not in front of the whole club. I pulled her behind a tower of equipment in the corner of the DJ booth and we attacked each other, just a few feet away from where my friend was DJing. She put my hand up her skirt and she was so wet she had soaked her panties. As I started to finger her she stuck her hand inside my pants to stroke my hard cock. Next thing I know, she'd undone my pants, freed my raging erection and slipped it into her wet pussy. She was just a bit taller than me with heels on so it worked perfectly. After a hot, quick shag we got ourselves dressed and somewhat put back together, then rejoined the gang in the main part of the DJ booth. Funniest part was that they didn't even notice we'd been gone! When I told my buddy about it later he said he had no idea. Fun times!