When a Caucasian, or generally light-skinned person, accidentally defecates themselves. The resulting aftermath resembles an Uh-Oh Oreo(white sandwich cookies with chocolate creme filling) Their ass-cheeks are the white cookies, and the shit is the chocolate filling.
Matt: Dude, are you okay?
Scott: No, I think I just made an uh-oh oreo. Why did I wear khakistoday?!
when you take a shit underneath a bed's mattress pad and then also between the mattress and the box spring. the victim will first discover the fecal matter under the mattress pad, and they will believe that the issue is rectified after cleaning that up. for a period of time afterwards, hopefully several weeks, the victim will continue to discover a foul smell, before they eventually realize the second deposit underneath the mattress.
this phenomenon resembles an Oreo where the mattress is the white filling between the two layers of chocolate.
"I just found out that my man has been cheating on me. it's time to go to his house and leave him an unpleasant surprise. I hope that him and his new lady friend enjoy discovering this Uh-Oh Oreo!"