Said by absolute wankers and utter cunts feeling smug and clever
A: says joke B: scratches head
A: if you know, you know - and doesn't explain. There's a superior undertone, supposedly to manipulate the listener into giving AF. Said usually by completely banal people with nothing to show for their total and self-absorbed mediocrity
What you say after you have informed someone with information they did not know
"Wow I never learned that men have the same thing that's inside of a vagina is inside of our assholes in my health class." "Now you know". " why didn't they teach us that? This whole time I could been using my vagina that's in my ass".