Reminds me of an issue which must bother most mongers who trawl the myriad massage shops in LOS that tempt but offer no more privacy than a curtain or a wall that does not reach the ceiling. The tell-tale noises that conjure up visions of an ecstatic "massage" on the other side. Noises that I have heard include soft sighs, sotto voce chuckles, the sucking noise made by the plastic bottle as she squeezes out oil (!). Once I even heard a slurping sound which made my massage girl contort with silent laughter as she looked at me with a glint in her eye to indicate she knew what was going on.
The noisiest sex I had was in SOL. The girl of my choice was happily bouncing on my lap with not a stitch on her and the bar was filled with the clapping sounds of her soft bottom hitting my thighs (which was quite loud given the size of the bar). On top of that she was moaning too. When we changed to missionary, I didnt bother to reducing the sounds either. We f***ed in bliss, making all the noise we could. No one seemed to be bothered.