2. Pussy lips. By analogy to calling them flaps. See? flaps... slats... Now... flaps everybody understands, but *slats*?... Gimme a break!... Please don't call your girlfriend's pussy lips *slats* if you don't want to sound awfully nerdy, or unless you both work at Lockheed-Martin.
2. (Youre giving her head on the drawing board late at night at Lockheed-Martin) Hmm Donna, these slats are hot! Not the ones in your design dummy!