Agreed! Part of the erotic attraction to being in mud is the sound it makes. Some folks are unfortunate in silencing their videos. This takes away from the excitement.
I don't know what it is about that stuff sliding down over your/my head that turns me on. I always use to sit in a deep mud hole constantly piling globs of it over my head while I jerked off.
MIR is MR. International Rubber. It's a gay convention held every fall in Chicago for rubber fetishists. They have various activities like the one above. Google it.
You're lucky to have a friend who enjoys it like you. I've only been able to drag my partner in the mud a couple times and he acts like he can't wait to get out to shower.