Mouth noises plain and simple. I’m talking chewing, lip smacking, sucking of the teeth to clean em. These to me sound like styrofoam.
I worked a season with this dude named, no joke, Dick Ball. This guy was an incredibly competent all around skilled laborer but he grew up working in saw mills and logging crews in the 80s/90s and definitely saw a fair share of crank/meth use. He had this ingrained habit or neural tick nonstop smacking his lips when working. Didn't matter what we were doing, digging holes, splitting wood, working on a vehicle, whatever. You ask him a question or whatever and he'd pop right out and answer the question, teach whatever you need to know, and get back to lip smacking. Dude only did it while working. It was pretty gross