Running around a campfire or bonfire while farting the whole time, thus producing a circle of crap smell for everyone around the fire to enjoy.
Origin: This weekend camping, crop dusting turned into a crop circle when I dusted everyone around the camp fire which then turned into the crap circle because it smelled like crap
Kevin ran around the campfire while farting, giving everyone a nice crap circle to enjoy.
circles on underwear, skivvies or other pantswear that show up and may be the work of aliens (such as Klingons or other off-world groups)
Mikey noticed that every morning when changing his underwear his dog Lucky would immediately start licking the mysterious crap circles that had appeared there.
The swirl designs that are left behind in the toilet after a hefty poop.
"Jesus! Who left all these crap circles? And when did we have corn?"