A line from Little Rascals made famous by Gordon Lee, who played Spanky's kid brother, Porky. Lee's signature line, "Otay, Panky," came about because he had a speech impediment and couldn't say his K's and S's.
Currently thr phrase could be used as an affirmative reply when someone tells you something fairly obvious. It's a silly way of saying "okay."
Bob: "Don't walk in the steet because you might get hit by a car."
Anything which can happen between a couple. There is no set definition as to what it may be, but it can be said that it issomething that someone who is not part of the couple would not want to be around when it is occurring.