Whilst someone slumbers, you clevery sneak up on them and lay a deuce(taking a shit) on their face. Then either get the f*ck out of there, or pretend you dont know how it happened when they wake up.
"Hey man, Charlie fell asleep early. Lets go play brown-eye peek-a-boo."
a peek-a-boo is when you brown eye (or moon) a person and squeeze a poo out and suck it back up your arse.
harry the dirty prick was pissed last night and peek-a-booed a car load of people on our way home from the pub.