As used in the 50's, the sweet or tangy goop that comes from a woman when she "gets off". Or, "gettin' some" from a female.
"Damn, her poo-tang pie tasted sooo good, it was sweet too, she must have been drinking orange juice!"
"Hey, rememba dat bitch i was tellin ya'll 'bout!!? Well, she finally let me take a dip into her poo-tang pie and it was off the chain!"