I was out at a club with my girlfriend and while we were eating she was showing a flash of stocking top as the flap at the side of her skirt fell. She had all black underwear on that night except her panties which were red. I noticed one particular guy spot her and when I told her, I said for her to cross her legs and let the skirt slide up a touch. As she'd had a fair bit to drink, I took the plunge and asked if she was up for what we had fantasised about so often. Yes, off you go she said and I'll have him in there within 15 minutes. I left her there with the pretence of a disagreement. I made my way out to the toilets and waited. I found out later that her admirer had come over after I'd been gone quite some time and offered to buy her a drink. He asked about me and if I would mind. She said I was only a friend anyway but as we'd had a row she couldn't care less. They had a couple of dances and he asked if could take her home. She told him she couldn't wait that long and to follow her to the toilets. I heard them get into the next cubicle and there was a lot of rustling of clothes and heavy breathing. I peeped underneath and saw her red panties round her ankles. Suddelly the partition was banging and rocking as they were fucking. It was incredible to be so close to seeing her getting fucked but only being able to hear it. I let them return into the club and came back in shortly afterwards. I sat at a distance away. She came over and we pretended to have a conversation. She went back to the guy, told him she was leaving with me but she hoped he'd enjoyed it as much as she had. On the way back I felt up her cunt and could sense the spunk that was up there. Her panties had gone but she told me the guy had kept them. What a superb session we had when we got in!