When taking a shower in the locker room while another person is simultaneously dropping a hot and smelly deuce in a nearby stall. The steam of the shower and the stench of the poop combine to engulf you in a thick, warm turd fog from which there is no escape.
thun·der·head, n. The swollen upper portion of a thundercloud, usually only recognized by people who enjoy having great breadth, but little depth of knowledge.