poop spikes
Strange pointy spikes that appear when a tight shirt is worn over pants or shorts that have a lot of buttons, pockets, accecories, etc. on the back, and kind of looks like crap sticking out from behind the shirt.
"Yo that kid's crazy wearin that tight shirt over those cargo shorts"
"Yeah, man! Look at the poop spikes stickin' out the back!"
"Yeah, man! Look at the poop spikes stickin' out the back!"