The wet,
brown, sticky substance puddled on the floor after a mosh-pit has cleared.
Normally consisted of
dirt, spit, sweat, booze, and very possibly
blood.
Friend#1:
Oh, dude gross. I have mosh juice all over my shoes from that concert last night.
Friend#2: Yeah, I got knocked over in the pit and some got on my arm. I dare you to smell it.