When someone is passed out or asleep and someone else pulls down their underwear and takes a shit in it before pulling the underwear back up so when they wake up they think they've shit themselves. Can also be done in their bed.
My lightweight mate crashed out after some beers and luckily was face down on the sofa, too good an opportunity to miss. I had a turd on the cusp so pulled his kecks down and laid a cuckoo poo in them. I then pulled his pants back up and smothered it in before slapping him awake shouting 'you dirty bastard, look what you've done, you've stunk out the room!!". Mortified he didn't show his face for a while and still thinks my cuckoo poo was his.
by Jean Dom February 25, 2010
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