What is Drop Off The Cosby Kids At The Pool?
1.
to have a bowel movement, to take a shit, to take a crap, etc...
"yo i'll be right back i gotta go drop the cosby kids off at the pool"
See
2.
the act of crapping
Dude, where's the bathroom. After that pizza and those 40 ouncers I've got to drop off the Cosby kids at the pool.