The mark made by a wet fart, skidmark
At the end of the day while Johnny was changing his clothes ,he had noticed his bad gas had made a rather large fart print in his shorts. Better change those shorts before your night at the bar Johnny.
When one farts and the moisture left behind can lead one to believe they have made a Rorschach in their underwear ,or their ass crack.
Johnny had a gargantuan fart he let loose ,and now believes he has made a Rorschach fart in his pants.
when douchebag frat guys are hazing each other,in this ritual much like elephanst in a row the men take their pants off and insert one thumb in the males ass in front of them and insert their other thumb in their mouth. Than they proceed to walk as circus elephants in a row,when the first douchebag's thumb to fall out of the first one's asshole,they must replace it with the thumb that was once in their mouth and replace it with the soiled thumb
Man we were hazing the fresh-meat at the house last night and three of them got sick from the elephant walk we made them pull!