a bad or unenjoyable thing, event, or smell; derived from the powdery film left under your fingernail after having scratched the upper part of your buttcrack and not having showered for a while.
"Man, that last game of Mario Kart was poo-poo cheese! I only got hit with red shells the whole time!"
or
"Oh my god, that smells like absolute poo-poo cheese."
or
"I'm playing insert game here like ass today."
"Yeah man, you're poo-poo cheese right now."
Getting head in an unlit parking lot, in the back of a El Camino. Only to find out when the lights came on it was your buddy his mustache shaved off.
You tricked me! Shaved off your mustache to give some mexican head cheese.