Phonetics... Sibilants and fricatives

Does anybody understand phonetics? I'm trying to sort out all the sounds in all the languages on earth, and I'm beginning to suspect I'm out of my depth.

Skin Lotion Relativism

Has anyone ever noticed that if you put skin lotion of one part of your body, all the other parts start feeling dry? 

Do you think anyone's done any research into this? My preliminary searches don't tell me--it's hard to search for!